//
//  peglib.h
//
//  Copyright (c) 2022 Yuji Hirose. All rights reserved.
//  MIT License
//

#pragma once

/*
 * Configuration
 */

#ifndef CPPPEGLIB_HEURISTIC_ERROR_TOKEN_MAX_CHAR_COUNT
#define CPPPEGLIB_HEURISTIC_ERROR_TOKEN_MAX_CHAR_COUNT 32
#endif

#include <algorithm>
#include <any>
#include <cassert>
#include <cctype>
#if __has_include(<charconv>)
#include <charconv>
#endif
#include <cstring>
#include <functional>
#include <initializer_list>
#include <iostream>
#include <limits>
#include <map>
#include <memory>
#include <mutex>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#if !defined(__cplusplus) || __cplusplus < 201703L
#error "Requires complete C++17 support"
#endif

namespace peg {

/*-----------------------------------------------------------------------------
 *  scope_exit
 *---------------------------------------------------------------------------*/

// This is based on
// "http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4189".

template <typename EF> struct scope_exit {
    explicit scope_exit(EF &&f)
        : exit_function(std::move(f)), execute_on_destruction{true} {}

    scope_exit(scope_exit &&rhs)
        : exit_function(std::move(rhs.exit_function)),
          execute_on_destruction{rhs.execute_on_destruction} {
        rhs.release();
    }

    ~scope_exit() {
        if (execute_on_destruction) { this->exit_function(); }
    }

    void release() { this->execute_on_destruction = false; }

private:
    scope_exit(const scope_exit &) = delete;
    void operator=(const scope_exit &) = delete;
    scope_exit &operator=(scope_exit &&) = delete;

    EF exit_function;
    bool execute_on_destruction;
};

/*-----------------------------------------------------------------------------
 *  UTF8 functions
 *---------------------------------------------------------------------------*/

inline size_t codepoint_length(const char *s8, size_t l) {
    if (l) {
        auto b = static_cast<uint8_t>(s8[0]);
        if ((b & 0x80) == 0) {
            return 1;
        } else if ((b & 0xE0) == 0xC0 && l >= 2) {
            return 2;
        } else if ((b & 0xF0) == 0xE0 && l >= 3) {
            return 3;
        } else if ((b & 0xF8) == 0xF0 && l >= 4) {
            return 4;
        }
    }
    return 0;
}

inline size_t codepoint_count(const char *s8, size_t l) {
    size_t count = 0;
    for (size_t i = 0; i < l; i += codepoint_length(s8 + i, l - i)) {
        count++;
    }
    return count;
}

inline size_t encode_codepoint(char32_t cp, char *buff) {
    if (cp < 0x0080) {
        buff[0] = static_cast<char>(cp & 0x7F);
        return 1;
    } else if (cp < 0x0800) {
        buff[0] = static_cast<char>(0xC0 | ((cp >> 6) & 0x1F));
        buff[1] = static_cast<char>(0x80 | (cp & 0x3F));
        return 2;
    } else if (cp < 0xD800) {
        buff[0] = static_cast<char>(0xE0 | ((cp >> 12) & 0xF));
        buff[1] = static_cast<char>(0x80 | ((cp >> 6) & 0x3F));
        buff[2] = static_cast<char>(0x80 | (cp & 0x3F));
        return 3;
    } else if (cp < 0xE000) {
        // D800 - DFFF is invalid...
        return 0;
    } else if (cp < 0x10000) {
        buff[0] = static_cast<char>(0xE0 | ((cp >> 12) & 0xF));
        buff[1] = static_cast<char>(0x80 | ((cp >> 6) & 0x3F));
        buff[2] = static_cast<char>(0x80 | (cp & 0x3F));
        return 3;
    } else if (cp < 0x110000) {
        buff[0] = static_cast<char>(0xF0 | ((cp >> 18) & 0x7));
        buff[1] = static_cast<char>(0x80 | ((cp >> 12) & 0x3F));
        buff[2] = static_cast<char>(0x80 | ((cp >> 6) & 0x3F));
        buff[3] = static_cast<char>(0x80 | (cp & 0x3F));
        return 4;
    }
    return 0;
}

inline std::string encode_codepoint(char32_t cp) {
    char buff[4];
    auto l = encode_codepoint(cp, buff);
    return std::string(buff, l);
}

inline bool decode_codepoint(const char *s8, size_t l, size_t &bytes,
                             char32_t &cp) {
    if (l) {
        auto b = static_cast<uint8_t>(s8[0]);
        if ((b & 0x80) == 0) {
            bytes = 1;
            cp = b;
            return true;
        } else if ((b & 0xE0) == 0xC0) {
            if (l >= 2) {
                bytes = 2;
                cp = ((static_cast<char32_t>(s8[0] & 0x1F)) << 6) |
                     (static_cast<char32_t>(s8[1] & 0x3F));
                return true;
            }
        } else if ((b & 0xF0) == 0xE0) {
            if (l >= 3) {
                bytes = 3;
                cp = ((static_cast<char32_t>(s8[0] & 0x0F)) << 12) |
                     ((static_cast<char32_t>(s8[1] & 0x3F)) << 6) |
                     (static_cast<char32_t>(s8[2] & 0x3F));
                return true;
            }
        } else if ((b & 0xF8) == 0xF0) {
            if (l >= 4) {
                bytes = 4;
                cp = ((static_cast<char32_t>(s8[0] & 0x07)) << 18) |
                     ((static_cast<char32_t>(s8[1] & 0x3F)) << 12) |
                     ((static_cast<char32_t>(s8[2] & 0x3F)) << 6) |
                     (static_cast<char32_t>(s8[3] & 0x3F));
                return true;
            }
        }
    }
    return false;
}

inline size_t decode_codepoint(const char *s8, size_t l, char32_t &cp) {
    size_t bytes;
    if (decode_codepoint(s8, l, bytes, cp)) { return bytes; }
    return 0;
}

inline char32_t decode_codepoint(const char *s8, size_t l) {
    char32_t cp = 0;
    decode_codepoint(s8, l, cp);
    return cp;
}

inline std::u32string decode(const char *s8, size_t l) {
    std::u32string out;
    size_t i = 0;
    while (i < l) {
        auto beg = i++;
        while (i < l && (s8[i] & 0xc0) == 0x80) {
            i++;
        }
        out += decode_codepoint(&s8[beg], (i - beg));
    }
    return out;
}

template <typename T> const char *u8(const T *s) {
    return reinterpret_cast<const char *>(s);
}

/*-----------------------------------------------------------------------------
 *  escape_characters
 *---------------------------------------------------------------------------*/

inline std::string escape_characters(const char *s, size_t n) {
    std::string str;
    for (size_t i = 0; i < n; i++) {
        auto c = s[i];
        switch (c) {
            case '\f': str += "\\f"; break;
            case '\n': str += "\\n"; break;
            case '\r': str += "\\r"; break;
            case '\t': str += "\\t"; break;
            case '\v': str += "\\v"; break;
            default: str += c; break;
        }
    }
    return str;
}

inline std::string escape_characters(std::string_view sv) {
    return escape_characters(sv.data(), sv.size());
}

/*-----------------------------------------------------------------------------
 *  resolve_escape_sequence
 *---------------------------------------------------------------------------*/

inline bool is_hex(char c, int &v) {
    if ('0' <= c && c <= '9') {
        v = c - '0';
        return true;
    } else if ('a' <= c && c <= 'f') {
        v = c - 'a' + 10;
        return true;
    } else if ('A' <= c && c <= 'F') {
        v = c - 'A' + 10;
        return true;
    }
    return false;
}

inline bool is_digit(char c, int &v) {
    if ('0' <= c && c <= '9') {
        v = c - '0';
        return true;
    }
    return false;
}

inline std::pair<int, size_t> parse_hex_number(const char *s, size_t n,
                                               size_t i) {
    int ret = 0;
    int val;
    while (i < n && is_hex(s[i], val)) {
        ret = static_cast<int>(ret * 16 + val);
        i++;
    }
    return std::pair(ret, i);
}

inline std::pair<int, size_t> parse_octal_number(const char *s, size_t n,
                                                 size_t i) {
    int ret = 0;
    int val;
    while (i < n && is_digit(s[i], val)) {
        ret = static_cast<int>(ret * 8 + val);
        i++;
    }
    return std::pair(ret, i);
}

inline std::string resolve_escape_sequence(const char *s, size_t n) {
    std::string r;
    r.reserve(n);

    size_t i = 0;
    while (i < n) {
        auto ch = s[i];
        if (ch == '\\') {
            i++;
            if (i == n) { throw std::runtime_error("Invalid escape sequence..."); }
            switch (s[i]) {
                case 'f':
                    r += '\f';
                    i++;
                    break;
                case 'n':
                    r += '\n';
                    i++;
                    break;
                case 'r':
                    r += '\r';
                    i++;
                    break;
                case 't':
                    r += '\t';
                    i++;
                    break;
                case 'v':
                    r += '\v';
                    i++;
                    break;
                case '\'':
                    r += '\'';
                    i++;
                    break;
                case '"':
                    r += '"';
                    i++;
                    break;
                case '[':
                    r += '[';
                    i++;
                    break;
                case ']':
                    r += ']';
                    i++;
                    break;
                case '\\':
                    r += '\\';
                    i++;
                    break;
                case 'x':
                case 'u': {
                    char32_t cp;
                    std::tie(cp, i) = parse_hex_number(s, n, i + 1);
                    r += encode_codepoint(cp);
                    break;
                }
                default: {
                    char32_t cp;
                    std::tie(cp, i) = parse_octal_number(s, n, i);
                    r += encode_codepoint(cp);
                    break;
                }
            }
        } else {
            r += ch;
            i++;
        }
    }
    return r;
}

/*-----------------------------------------------------------------------------
 *  token_to_number_ - This function should be removed eventually
 *---------------------------------------------------------------------------*/

template <typename T> T token_to_number_(std::string_view sv) {
    T n = 0;
#if __has_include(<charconv>)
    if constexpr (!std::is_floating_point<T>::value) {
        std::from_chars(sv.data(), sv.data() + sv.size(), n);
#else
    if constexpr (false) {
#endif
    } else {
        auto s = std::string(sv);
        std::istringstream ss(s);
        ss >> n;
    }
    return n;
}

/*-----------------------------------------------------------------------------
 *  Trie
 *---------------------------------------------------------------------------*/

class Trie {
public:
    Trie(const std::vector<std::string> &items, bool ignore_case)
        : ignore_case_(ignore_case) {
        size_t id = 0;
        for (const auto &item : items) {
            const auto &s = ignore_case ? to_lower(item) : item;
            for (size_t len = 1; len <= item.size(); len++) {
                auto last = len == item.size();
                std::string_view sv(s.data(), len);
                auto it = dic_.find(sv);
                if (it == dic_.end()) {
                    dic_.emplace(sv, Info{last, last, id});
                } else if (last) {
                    it->second.match = true;
                } else {
                    it->second.done = false;
                }
            }
            id++;
        }
    }

    size_t match(const char *text, size_t text_len, size_t &id) const {
        std::string lower_text;
        if (ignore_case_) {
            lower_text = to_lower(text);
            text = lower_text.data();
        }

        size_t match_len = 0;
        auto done = false;
        size_t len = 1;
        while (!done && len <= text_len) {
            std::string_view sv(text, len);
            auto it = dic_.find(sv);
            if (it == dic_.end()) {
                done = true;
            } else {
                if (it->second.match) {
                    match_len = len;
                    id = it->second.id;
                }
                if (it->second.done) { done = true; }
            }
            len += 1;
        }
        return match_len;
    }

    size_t size() const { return dic_.size(); }

private:
    std::string to_lower(std::string s) const {
        for (char &c : s) {
            c = std::tolower(c);
        }
        return s;
    }

    struct Info {
        bool done;
        bool match;
        size_t id;
    };

    // TODO: Use unordered_map when heterogeneous lookup is supported in C++20
    // std::unordered_map<std::string, Info> dic_;
    std::map<std::string, Info, std::less<>> dic_;

    bool ignore_case_;
};

/*-----------------------------------------------------------------------------
 *  PEG
 *---------------------------------------------------------------------------*/

/*
 * Line information utility function
 */
inline std::pair<size_t, size_t> line_info(const char *start, const char *cur) {
    auto p = start;
    auto col_ptr = p;
    auto no = 1;

    while (p < cur) {
        if (*p == '\n') {
            no++;
            col_ptr = p + 1;
        }
        p++;
    }

    auto col = codepoint_count(col_ptr, p - col_ptr) + 1;

    return std::pair(no, col);
}

/*
 * String tag
 */
inline constexpr unsigned int str2tag_core(const char *s, size_t l,
                                           unsigned int h) {
    return (l == 0) ? h
                    : str2tag_core(s + 1, l - 1,
                                   (h * 33) ^ static_cast<unsigned char>(*s));
}

inline constexpr unsigned int str2tag(std::string_view sv) {
    return str2tag_core(sv.data(), sv.size(), 0);
}

namespace udl {

inline constexpr unsigned int operator"" _(const char *s, size_t l) {
    return str2tag_core(s, l, 0);
}

} // namespace udl

/*
 * Semantic values
 */
class Context;

struct SemanticValues : protected std::vector<std::any> {
    SemanticValues() = default;
    SemanticValues(Context *c) : c_(c) {}

    // Input text
    const char *path = nullptr;
    const char *ss = nullptr;

    // Matched string
    std::string_view sv() const { return sv_; }

    // Definition name
    const std::string &name() const { return name_; }

    std::vector<unsigned int> tags;

    // Line number and column at which the matched string is
    std::pair<size_t, size_t> line_info() const;

    // Choice count
    size_t choice_count() const { return choice_count_; }

    // Choice number (0 based index)
    size_t choice() const { return choice_; }

    // Tokens
    std::vector<std::string_view> tokens;

    std::string_view token(size_t id = 0) const {
        if (tokens.empty()) { return sv_; }
        assert(id < tokens.size());
        return tokens[id];
    }

    // Token conversion
    std::string token_to_string(size_t id = 0) const {
        return std::string(token(id));
    }

    template <typename T> T token_to_number() const {
        return token_to_number_<T>(token());
    }

    // Transform the semantic value vector to another vector
    template <typename T>
    std::vector<T> transform(size_t beg = 0,
                             size_t end = static_cast<size_t>(-1)) const {
        std::vector<T> r;
        end = (std::min)(end, size());
        for (size_t i = beg; i < end; i++) {
            r.emplace_back(std::any_cast<T>((*this)[i]));
        }
        return r;
    }

    void append(SemanticValues &chvs) {
        sv_ = chvs.sv_;
        for (auto &v : chvs) {
            emplace_back(std::move(v));
        }
        for (auto &tag : chvs.tags) {
            tags.emplace_back(std::move(tag));
        }
        for (auto &tok : chvs.tokens) {
            tokens.emplace_back(std::move(tok));
        }
    }

    using std::vector<std::any>::iterator;
    using std::vector<std::any>::const_iterator;
    using std::vector<std::any>::size;
    using std::vector<std::any>::empty;
    using std::vector<std::any>::assign;
    using std::vector<std::any>::begin;
    using std::vector<std::any>::end;
    using std::vector<std::any>::rbegin;
    using std::vector<std::any>::rend;
    using std::vector<std::any>::operator[];
    using std::vector<std::any>::at;
    using std::vector<std::any>::resize;
    using std::vector<std::any>::front;
    using std::vector<std::any>::back;
    using std::vector<std::any>::push_back;
    using std::vector<std::any>::pop_back;
    using std::vector<std::any>::insert;
    using std::vector<std::any>::erase;
    using std::vector<std::any>::clear;
    using std::vector<std::any>::swap;
    using std::vector<std::any>::emplace;
    using std::vector<std::any>::emplace_back;

private:
    friend class Context;
    friend class Dictionary;
    friend class Sequence;
    friend class PrioritizedChoice;
    friend class Repetition;
    friend class Holder;
    friend class PrecedenceClimbing;

    Context *c_ = nullptr;
    std::string_view sv_;
    size_t choice_count_ = 0;
    size_t choice_ = 0;
    std::string name_;
};

/*
 * Semantic action
 */
template <typename F, typename... Args> std::any call(F fn, Args &&...args) {
    using R = decltype(fn(std::forward<Args>(args)...));
    if constexpr (std::is_void<R>::value) {
        fn(std::forward<Args>(args)...);
        return std::any();
    } else if constexpr (std::is_same<typename std::remove_cv<R>::type,
                                      std::any>::value) {
        return fn(std::forward<Args>(args)...);
    } else {
        return std::any(fn(std::forward<Args>(args)...));
    }
}

template <typename T>
struct argument_count : argument_count<decltype(&T::operator())> {};
template <typename R, typename... Args>
struct argument_count<R (*)(Args...)>
    : std::integral_constant<unsigned, sizeof...(Args)> {};
template <typename R, typename C, typename... Args>
struct argument_count<R (C::*)(Args...)>
    : std::integral_constant<unsigned, sizeof...(Args)> {};
template <typename R, typename C, typename... Args>
struct argument_count<R (C::*)(Args...) const>
    : std::integral_constant<unsigned, sizeof...(Args)> {};

class Action {
public:
    Action() = default;
    Action(Action &&rhs) = default;
    template <typename F> Action(F fn) : fn_(make_adaptor(fn)) {}
    template <typename F> void operator=(F fn) { fn_ = make_adaptor(fn); }
    Action &operator=(const Action &rhs) = default;

    operator bool() const { return bool(fn_); }

    std::any operator()(SemanticValues &vs, std::any &dt) const {
        return fn_(vs, dt);
    }

private:
    using Fty = std::function<std::any(SemanticValues &vs, std::any &dt)>;

    template <typename F> Fty make_adaptor(F fn) {
        if constexpr (argument_count<F>::value == 1) {
            return [fn](auto &vs, auto & /*dt*/) { return call(fn, vs); };
        } else {
            return [fn](auto &vs, auto &dt) { return call(fn, vs, dt); };
        }
    }

    Fty fn_;
};

/*
 * Parse result helper
 */
inline bool success(size_t len) { return len != static_cast<size_t>(-1); }

inline bool fail(size_t len) { return len == static_cast<size_t>(-1); }

/*
 * Log
 */
using Log = std::function<void(size_t line, size_t col, const std::string &msg,
                               const std::string &rule)>;

/*
 * ErrorInfo
 */
class Definition;

struct ErrorInfo {
    const char *error_pos = nullptr;
    std::vector<std::pair<const char *, const Definition *>> expected_tokens;
    const char *message_pos = nullptr;
    std::string message;
    std::string label;
    const char *last_output_pos = nullptr;
    bool keep_previous_token = false;

    void clear() {
        error_pos = nullptr;
        expected_tokens.clear();
        message_pos = nullptr;
        message.clear();
    }

    void add(const char *error_literal, const Definition *error_rule) {
        for (const auto &[t, r] : expected_tokens) {
            if (t == error_literal && r == error_rule) { return; }
        }
        expected_tokens.emplace_back(error_literal, error_rule);
    }

    void output_log(const Log &log, const char *s, size_t n);

private:
    int cast_char(char c) const { return static_cast<unsigned char>(c); }

    std::string heuristic_error_token(const char *s, size_t n,
                                      const char *pos) const {
        auto len = n - std::distance(s, pos);
        if (len) {
            size_t i = 0;
            auto c = cast_char(pos[i++]);
            if (!std::ispunct(c) && !std::isspace(c)) {
                while (i < len && !std::ispunct(cast_char(pos[i])) &&
                       !std::isspace(cast_char(pos[i]))) {
                    i++;
                }
            }

            size_t count = CPPPEGLIB_HEURISTIC_ERROR_TOKEN_MAX_CHAR_COUNT;
            size_t j = 0;
            while (count > 0 && j < i) {
                j += codepoint_length(&pos[j], i - j);
                count--;
            }

            return escape_characters(pos, j);
        }
        return std::string();
    }

    std::string replace_all(std::string str, const std::string &from,
                            const std::string &to) const {
        size_t pos = 0;
        while ((pos = str.find(from, pos)) != std::string::npos) {
            str.replace(pos, from.length(), to);
            pos += to.length();
        }
        return str;
    }
};

/*
 * Context
 */
class Ope;

using TracerEnter = std::function<void(
    const Ope &name, const char *s, size_t n, const SemanticValues &vs,
    const Context &c, const std::any &dt, std::any &trace_data)>;

using TracerLeave = std::function<void(
    const Ope &ope, const char *s, size_t n, const SemanticValues &vs,
    const Context &c, const std::any &dt, size_t, std::any &trace_data)>;

using TracerStartOrEnd = std::function<void(std::any &trace_data)>;

class Context {
public:
    const char *path;
    const char *s;
    const size_t l;

    ErrorInfo error_info;
    bool recovered = false;

    std::vector<std::shared_ptr<SemanticValues>> value_stack;
    size_t value_stack_size = 0;

    std::vector<Definition *> rule_stack;
    std::vector<std::vector<std::shared_ptr<Ope>>> args_stack;

    size_t in_token_boundary_count = 0;

    std::shared_ptr<Ope> whitespaceOpe;
    bool in_whitespace = false;

    std::shared_ptr<Ope> wordOpe;

    std::vector<std::map<std::string_view, std::string>> capture_scope_stack;
    size_t capture_scope_stack_size = 0;

    std::vector<bool> cut_stack;

    const size_t def_count;
    const bool enablePackratParsing;
    std::vector<bool> cache_registered;
    std::vector<bool> cache_success;

    std::map<std::pair<size_t, size_t>, std::tuple<size_t, std::any>>
        cache_values;

    TracerEnter tracer_enter;
    TracerLeave tracer_leave;
    std::any trace_data;
    const bool verbose_trace;

    Log log;

    Context(const char *path, const char *s, size_t l, size_t def_count,
            std::shared_ptr<Ope> whitespaceOpe, std::shared_ptr<Ope> wordOpe,
            bool enablePackratParsing, TracerEnter tracer_enter,
            TracerLeave tracer_leave, std::any trace_data, bool verbose_trace,
            Log log)
        : path(path), s(s), l(l), whitespaceOpe(whitespaceOpe), wordOpe(wordOpe),
          def_count(def_count), enablePackratParsing(enablePackratParsing),
          cache_registered(enablePackratParsing ? def_count * (l + 1) : 0),
          cache_success(enablePackratParsing ? def_count * (l + 1) : 0),
          tracer_enter(tracer_enter), tracer_leave(tracer_leave),
          trace_data(trace_data), verbose_trace(verbose_trace), log(log) {

        push_args({});
        push_capture_scope();
    }

    ~Context() {
        pop_capture_scope();

        assert(!value_stack_size);
        assert(!capture_scope_stack_size);
        assert(cut_stack.empty());
    }

    Context(const Context &) = delete;
    Context(Context &&) = delete;
    Context operator=(const Context &) = delete;

    template <typename T>
    void packrat(const char *a_s, size_t def_id, size_t &len, std::any &val,
                 T fn) {
        if (!enablePackratParsing) {
            fn(val);
            return;
        }

        auto col = a_s - s;
        auto idx = def_count * static_cast<size_t>(col) + def_id;

        if (cache_registered[idx]) {
            if (cache_success[idx]) {
                auto key = std::pair(col, def_id);
                std::tie(len, val) = cache_values[key];
                return;
            } else {
                len = static_cast<size_t>(-1);
                return;
            }
        } else {
            fn(val);
            cache_registered[idx] = true;
            cache_success[idx] = success(len);
            if (success(len)) {
                auto key = std::pair(col, def_id);
                cache_values[key] = std::pair(len, val);
            }
            return;
        }
    }

    SemanticValues &push() {
        push_capture_scope();
        return push_semantic_values_scope();
    }

    void pop() {
        pop_capture_scope();
        pop_semantic_values_scope();
    }

    // Semantic values
    SemanticValues &push_semantic_values_scope() {
        assert(value_stack_size <= value_stack.size());
        if (value_stack_size == value_stack.size()) {
            value_stack.emplace_back(std::make_shared<SemanticValues>(this));
        } else {
            auto &vs = *value_stack[value_stack_size];
            if (!vs.empty()) {
                vs.clear();
                if (!vs.tags.empty()) { vs.tags.clear(); }
            }
            vs.sv_ = std::string_view();
            vs.choice_count_ = 0;
            vs.choice_ = 0;
            if (!vs.tokens.empty()) { vs.tokens.clear(); }
        }

        auto &vs = *value_stack[value_stack_size++];
        vs.path = path;
        vs.ss = s;
        return vs;
    }

    void pop_semantic_values_scope() { value_stack_size--; }

    // Arguments
    void push_args(std::vector<std::shared_ptr<Ope>> &&args) {
        args_stack.emplace_back(args);
    }

    void pop_args() { args_stack.pop_back(); }

    const std::vector<std::shared_ptr<Ope>> &top_args() const {
        return args_stack[args_stack.size() - 1];
    }

    // Capture scope
    void push_capture_scope() {
        assert(capture_scope_stack_size <= capture_scope_stack.size());
        if (capture_scope_stack_size == capture_scope_stack.size()) {
            capture_scope_stack.emplace_back(
                std::map<std::string_view, std::string>());
        } else {
            auto &cs = capture_scope_stack[capture_scope_stack_size];
            if (!cs.empty()) { cs.clear(); }
        }
        capture_scope_stack_size++;
    }

    void pop_capture_scope() { capture_scope_stack_size--; }

    void shift_capture_values() {
        assert(capture_scope_stack_size >= 2);
        auto curr = &capture_scope_stack[capture_scope_stack_size - 1];
        auto prev = curr - 1;
        for (const auto &[k, v] : *curr) {
            (*prev)[k] = v;
        }
    }

    // Error
    void set_error_pos(const char *a_s, const char *literal = nullptr);

    // Trace
    void trace_enter(const Ope &ope, const char *a_s, size_t n,
                     const SemanticValues &vs, std::any &dt);
    void trace_leave(const Ope &ope, const char *a_s, size_t n,
                     const SemanticValues &vs, std::any &dt, size_t len);
    bool is_traceable(const Ope &ope) const;

    // Line info
    std::pair<size_t, size_t> line_info(const char *cur) const {
        std::call_once(source_line_index_init_, [this]() {
            for (size_t pos = 0; pos < l; pos++) {
                if (s[pos] == '\n') { source_line_index.push_back(pos); }
            }
            source_line_index.push_back(l);
        });

        auto pos = static_cast<size_t>(std::distance(s, cur));

        auto it = std::lower_bound(
            source_line_index.begin(), source_line_index.end(), pos,
            [](size_t element, size_t value) { return element < value; });

        auto id = static_cast<size_t>(std::distance(source_line_index.begin(), it));
        auto off = pos - (id == 0 ? 0 : source_line_index[id - 1] + 1);
        return std::pair(id + 1, off + 1);
    }

    size_t next_trace_id = 0;
    std::vector<size_t> trace_ids;
    bool ignore_trace_state = false;
    mutable std::once_flag source_line_index_init_;
    mutable std::vector<size_t> source_line_index;
};

/*
 * Parser operators
 */
class Ope {
public:
    struct Visitor;

    virtual ~Ope() = default;
    size_t parse(const char *s, size_t n, SemanticValues &vs, Context &c,
                 std::any &dt) const;
    virtual size_t parse_core(const char *s, size_t n, SemanticValues &vs,
                              Context &c, std::any &dt) const = 0;
    virtual void accept(Visitor &v) = 0;
};

class Sequence : public Ope {
public:
    template <typename... Args>
    Sequence(const Args &...args)
        : opes_{static_cast<std::shared_ptr<Ope>>(args)...} {}
    Sequence(const std::vector<std::shared_ptr<Ope>> &opes) : opes_(opes) {}
    Sequence(std::vector<std::shared_ptr<Ope>> &&opes) : opes_(opes) {}

    size_t parse_core(const char *s, size_t n, SemanticValues &vs, Context &c,
                      std::any &dt) const override {
        auto &chvs = c.push_semantic_values_scope();
        auto se = scope_exit([&]() { c.pop_semantic_values_scope(); });
        size_t i = 0;
        for (const auto &ope : opes_) {
            auto len = ope->parse(s + i, n - i, chvs, c, dt);
            if (fail(len)) { return len; }
            i += len;
        }
        vs.append(chvs);
        return i;
    }

    void accept(Visitor &v) override;

    std::vector<std::shared_ptr<Ope>> opes_;
};

class PrioritizedChoice : public Ope {
public:
    template <typename... Args>
    PrioritizedChoice(bool for_label, const Args &...args)
        : opes_{static_cast<std::shared_ptr<Ope>>(args)...},
          for_label_(for_label) {}
    PrioritizedChoice(const std::vector<std::shared_ptr<Ope>> &opes)
        : opes_(opes) {}
    PrioritizedChoice(std::vector<std::shared_ptr<Ope>> &&opes) : opes_(opes) {}

    size_t parse_core(const char *s, size_t n, SemanticValues &vs, Context &c,
                      std::any &dt) const override {
        size_t len = static_cast<size_t>(-1);

        if (!for_label_) { c.cut_stack.push_back(false); }
        auto se1 = scope_exit([&]() {
            if (!for_label_) { c.cut_stack.pop_back(); }
        });

        size_t id = 0;
        for (const auto &ope : opes_) {
            if (!c.cut_stack.empty()) { c.cut_stack.back() = false; }

            auto &chvs = c.push();
            c.error_info.keep_previous_token = id > 0;
            auto se2 = scope_exit([&]() {
                c.pop();
                c.error_info.keep_previous_token = false;
            });

            len = ope->parse(s, n, chvs, c, dt);

            if (success(len)) {
                vs.append(chvs);
                vs.choice_count_ = opes_.size();
                vs.choice_ = id;
                c.shift_capture_values();
                break;
            } else if (!c.cut_stack.empty() && c.cut_stack.back()) {
                break;
            }

            id++;
        }

        return len;
    }

    void accept(Visitor &v) override;

    size_t size() const { return opes_.size(); }

    std::vector<std::shared_ptr<Ope>> opes_;
    bool for_label_ = false;
};

class Repetition : public Ope {
public:
    Repetition(const std::shared_ptr<Ope> &ope, size_t min, size_t max)
        : ope_(ope), min_(min), max_(max) {}

    size_t parse_core(const char *s, size_t n, SemanticValues &vs, Context &c,
                      std::any &dt) const override {
        size_t count = 0;
        size_t i = 0;
        while (count < min_) {
            auto &chvs = c.push();
            auto se = scope_exit([&]() { c.pop(); });

            auto len = ope_->parse(s + i, n - i, chvs, c, dt);

            if (success(len)) {
                vs.append(chvs);
                c.shift_capture_values();
            } else {
                return len;
            }
            i += len;
            count++;
        }

        while (count < max_) {
            auto &chvs = c.push();
            auto se = scope_exit([&]() { c.pop(); });

            auto len = ope_->parse(s + i, n - i, chvs, c, dt);

            if (success(len)) {
                vs.append(chvs);
                c.shift_capture_values();
            } else {
                break;
            }
            i += len;
            count++;
        }
        return i;
    }

    void accept(Visitor &v) override;

    bool is_zom() const {
        return min_ == 0 && max_ == std::numeric_limits<size_t>::max();
    }

    static std::shared_ptr<Repetition> zom(const std::shared_ptr<Ope> &ope) {
        return std::make_shared<Repetition>(ope, 0,
                                            std::numeric_limits<size_t>::max());
    }

    static std::shared_ptr<Repetition> oom(const std::shared_ptr<Ope> &ope) {
        return std::make_shared<Repetition>(ope, 1,
                                            std::numeric_limits<size_t>::max());
    }

    static std::shared_ptr<Repetition> opt(const std::shared_ptr<Ope> &ope) {
        return std::make_shared<Repetition>(ope, 0, 1);
    }

    std::shared_ptr<Ope> ope_;
    size_t min_;
    size_t max_;
};

class AndPredicate : public Ope {
public:
    AndPredicate(const std::shared_ptr<Ope> &ope) : ope_(ope) {}

    size_t parse_core(const char *s, size_t n, SemanticValues & /*vs*/,
                      Context &c, std::any &dt) const override {
        auto &chvs = c.push();
        auto se = scope_exit([&]() { c.pop(); });

        auto len = ope_->parse(s, n, chvs, c, dt);

        if (success(len)) {
            return 0;
        } else {
            return len;
        }
    }

    void accept(Visitor &v) override;

    std::shared_ptr<Ope> ope_;
};

class NotPredicate : public Ope {
public:
    NotPredicate(const std::shared_ptr<Ope> &ope) : ope_(ope) {}

    size_t parse_core(const char *s, size_t n, SemanticValues & /*vs*/,
                      Context &c, std::any &dt) const override {
        auto &chvs = c.push();
        auto se = scope_exit([&]() { c.pop(); });
        auto len = ope_->parse(s, n, chvs, c, dt);
        if (success(len)) {
            c.set_error_pos(s);
            return static_cast<size_t>(-1);
        } else {
            return 0;
        }
    }

    void accept(Visitor &v) override;

    std::shared_ptr<Ope> ope_;
};

class Dictionary : public Ope, public std::enable_shared_from_this<Dictionary> {
public:
    Dictionary(const std::vector<std::string> &v, bool ignore_case)
        : trie_(v, ignore_case) {}

    size_t parse_core(const char *s, size_t n, SemanticValues &vs, Context &c,
                      std::any &dt) const override;

    void accept(Visitor &v) override;

    Trie trie_;
};

class LiteralString : public Ope,
                      public std::enable_shared_from_this<LiteralString> {
public:
    LiteralString(std::string &&s, bool ignore_case)
        : lit_(s), ignore_case_(ignore_case), is_word_(false) {}

    LiteralString(const std::string &s, bool ignore_case)
        : lit_(s), ignore_case_(ignore_case), is_word_(false) {}

    size_t parse_core(const char *s, size_t n, SemanticValues &vs, Context &c,
                      std::any &dt) const override;

    void accept(Visitor &v) override;

    std::string lit_;
    bool ignore_case_;
    mutable std::once_flag init_is_word_;
    mutable bool is_word_;
};

class CharacterClass : public Ope,
                       public std::enable_shared_from_this<CharacterClass> {
public:
    CharacterClass(const std::string &s, bool negated, bool ignore_case)
        : negated_(negated), ignore_case_(ignore_case) {
        auto chars = decode(s.data(), s.length());
        auto i = 0u;
        while (i < chars.size()) {
            if (i + 2 < chars.size() && chars[i + 1] == '-') {
                auto cp1 = chars[i];
                auto cp2 = chars[i + 2];
                ranges_.emplace_back(std::pair(cp1, cp2));
                i += 3;
            } else {
                auto cp = chars[i];
                ranges_.emplace_back(std::pair(cp, cp));
                i += 1;
            }
        }
        assert(!ranges_.empty());
    }

    CharacterClass(const std::vector<std::pair<char32_t, char32_t>> &ranges,
                   bool negated, bool ignore_case)
        : ranges_(ranges), negated_(negated), ignore_case_(ignore_case) {
        assert(!ranges_.empty());
    }

    size_t parse_core(const char *s, size_t n, SemanticValues & /*vs*/,
                      Context &c, std::any & /*dt*/) const override {
        if (n < 1) {
            c.set_error_pos(s);
            return static_cast<size_t>(-1);
        }

        char32_t cp = 0;
        auto len = decode_codepoint(s, n, cp);

        for (const auto &range : ranges_) {
            if (in_range(range, cp)) {
                if (negated_) {
                    c.set_error_pos(s);
                    return static_cast<size_t>(-1);
                } else {
                    return len;
                }
            }
        }

        if (negated_) {
            return len;
        } else {
            c.set_error_pos(s);
            return static_cast<size_t>(-1);
        }
    }

    void accept(Visitor &v) override;

private:
    bool in_range(const std::pair<char32_t, char32_t> &range, char32_t cp) const {
        if (ignore_case_) {
            auto cpl = std::tolower(cp);
            return std::tolower(range.first) <= cpl &&
                   cpl <= std::tolower(range.second);
        } else {
            return range.first <= cp && cp <= range.second;
        }
    }

    std::vector<std::pair<char32_t, char32_t>> ranges_;
    bool negated_;
    bool ignore_case_;
};

class Character : public Ope, public std::enable_shared_from_this<Character> {
public:
    Character(char ch) : ch_(ch) {}

    size_t parse_core(const char *s, size_t n, SemanticValues & /*vs*/,
                      Context &c, std::any & /*dt*/) const override {
        if (n < 1 || s[0] != ch_) {
            c.set_error_pos(s);
            return static_cast<size_t>(-1);
        }
        return 1;
    }

    void accept(Visitor &v) override;

    char ch_;
};

class AnyCharacter : public Ope,
                     public std::enable_shared_from_this<AnyCharacter> {
public:
    size_t parse_core(const char *s, size_t n, SemanticValues & /*vs*/,
                      Context &c, std::any & /*dt*/) const override {
        auto len = codepoint_length(s, n);
        if (len < 1) {
            c.set_error_pos(s);
            return static_cast<size_t>(-1);
        }
        return len;
    }

    void accept(Visitor &v) override;
};

class CaptureScope : public Ope {
public:
    CaptureScope(const std::shared_ptr<Ope> &ope) : ope_(ope) {}

    size_t parse_core(const char *s, size_t n, SemanticValues &vs, Context &c,
                      std::any &dt) const override {
        c.push_capture_scope();
        auto se = scope_exit([&]() { c.pop_capture_scope(); });
        return ope_->parse(s, n, vs, c, dt);
    }

    void accept(Visitor &v) override;

    std::shared_ptr<Ope> ope_;
};

class Capture : public Ope {
public:
    using MatchAction = std::function<void(const char *s, size_t n, Context &c)>;

    Capture(const std::shared_ptr<Ope> &ope, MatchAction ma)
        : ope_(ope), match_action_(ma) {}

    size_t parse_core(const char *s, size_t n, SemanticValues &vs, Context &c,
                      std::any &dt) const override {
        auto len = ope_->parse(s, n, vs, c, dt);
        if (success(len) && match_action_) { match_action_(s, len, c); }
        return len;
    }

    void accept(Visitor &v) override;

    std::shared_ptr<Ope> ope_;
    MatchAction match_action_;
};

class TokenBoundary : public Ope {
public:
    TokenBoundary(const std::shared_ptr<Ope> &ope) : ope_(ope) {}

    size_t parse_core(const char *s, size_t n, SemanticValues &vs, Context &c,
                      std::any &dt) const override;

    void accept(Visitor &v) override;

    std::shared_ptr<Ope> ope_;
};

class Ignore : public Ope {
public:
    Ignore(const std::shared_ptr<Ope> &ope) : ope_(ope) {}

    size_t parse_core(const char *s, size_t n, SemanticValues & /*vs*/,
                      Context &c, std::any &dt) const override {
        auto &chvs = c.push_semantic_values_scope();
        auto se = scope_exit([&]() { c.pop_semantic_values_scope(); });
        return ope_->parse(s, n, chvs, c, dt);
    }

    void accept(Visitor &v) override;

    std::shared_ptr<Ope> ope_;
};

using Parser = std::function<size_t(const char *s, size_t n, SemanticValues &vs,
                                    std::any &dt)>;

class User : public Ope {
public:
    User(Parser fn) : fn_(fn) {}
    size_t parse_core(const char *s, size_t n, SemanticValues &vs,
                      Context & /*c*/, std::any &dt) const override {
        assert(fn_);
        return fn_(s, n, vs, dt);
    }
    void accept(Visitor &v) override;
    std::function<size_t(const char *s, size_t n, SemanticValues &vs,
                         std::any &dt)>
        fn_;
};

class WeakHolder : public Ope {
public:
    WeakHolder(const std::shared_ptr<Ope> &ope) : weak_(ope) {}

    size_t parse_core(const char *s, size_t n, SemanticValues &vs, Context &c,
                      std::any &dt) const override {
        auto ope = weak_.lock();
        assert(ope);
        return ope->parse(s, n, vs, c, dt);
    }

    void accept(Visitor &v) override;

    std::weak_ptr<Ope> weak_;
};

class Holder : public Ope {
public:
    Holder(Definition *outer) : outer_(outer) {}

    size_t parse_core(const char *s, size_t n, SemanticValues &vs, Context &c,
                      std::any &dt) const override;

    void accept(Visitor &v) override;

    std::any reduce(SemanticValues &vs, std::any &dt) const;

    const std::string &name() const;
    const std::string &trace_name() const;

    std::shared_ptr<Ope> ope_;
    Definition *outer_;
    mutable std::once_flag trace_name_init_;
    mutable std::string trace_name_;

    friend class Definition;
};

using Grammar = std::unordered_map<std::string, Definition>;

class Reference : public Ope, public std::enable_shared_from_this<Reference> {
public:
    Reference(const Grammar &grammar, const std::string &name, const char *s,
              bool is_macro, const std::vector<std::shared_ptr<Ope>> &args)
        : grammar_(grammar), name_(name), s_(s), is_macro_(is_macro), args_(args),
          rule_(nullptr), iarg_(0) {}

    size_t parse_core(const char *s, size_t n, SemanticValues &vs, Context &c,
                      std::any &dt) const override;

    void accept(Visitor &v) override;

    std::shared_ptr<Ope> get_core_operator() const;

    const Grammar &grammar_;
    const std::string name_;
    const char *s_;

    const bool is_macro_;
    const std::vector<std::shared_ptr<Ope>> args_;

    Definition *rule_;
    size_t iarg_;
};

class Whitespace : public Ope {
public:
    Whitespace(const std::shared_ptr<Ope> &ope) : ope_(ope) {}

    size_t parse_core(const char *s, size_t n, SemanticValues &vs, Context &c,
                      std::any &dt) const override {
        if (c.in_whitespace) { return 0; }
        c.in_whitespace = true;
        auto se = scope_exit([&]() { c.in_whitespace = false; });
        return ope_->parse(s, n, vs, c, dt);
    }

    void accept(Visitor &v) override;

    std::shared_ptr<Ope> ope_;
};

class BackReference : public Ope {
public:
    BackReference(std::string &&name) : name_(name) {}

    BackReference(const std::string &name) : name_(name) {}

    size_t parse_core(const char *s, size_t n, SemanticValues &vs, Context &c,
                      std::any &dt) const override;

    void accept(Visitor &v) override;

    std::string name_;
};

class PrecedenceClimbing : public Ope {
public:
    using BinOpeInfo = std::map<std::string_view, std::pair<size_t, char>>;

    PrecedenceClimbing(const std::shared_ptr<Ope> &atom,
                       const std::shared_ptr<Ope> &binop, const BinOpeInfo &info,
                       const Definition &rule)
        : atom_(atom), binop_(binop), info_(info), rule_(rule) {}

    size_t parse_core(const char *s, size_t n, SemanticValues &vs, Context &c,
                      std::any &dt) const override {
        return parse_expression(s, n, vs, c, dt, 0);
    }

    void accept(Visitor &v) override;

    std::shared_ptr<Ope> atom_;
    std::shared_ptr<Ope> binop_;
    BinOpeInfo info_;
    const Definition &rule_;

private:
    size_t parse_expression(const char *s, size_t n, SemanticValues &vs,
                            Context &c, std::any &dt, size_t min_prec) const;

    Definition &get_reference_for_binop(Context &c) const;
};

class Recovery : public Ope {
public:
    Recovery(const std::shared_ptr<Ope> &ope) : ope_(ope) {}

    size_t parse_core(const char *s, size_t n, SemanticValues &vs, Context &c,
                      std::any &dt) const override;

    void accept(Visitor &v) override;

    std::shared_ptr<Ope> ope_;
};

class Cut : public Ope, public std::enable_shared_from_this<Cut> {
public:
    size_t parse_core(const char * /*s*/, size_t /*n*/, SemanticValues & /*vs*/,
                      Context &c, std::any & /*dt*/) const override {
        if (!c.cut_stack.empty()) { c.cut_stack.back() = true; }
        return 0;
    }

    void accept(Visitor &v) override;
};

/*
 * Factories
 */
template <typename... Args> std::shared_ptr<Ope> seq(Args &&...args) {
    return std::make_shared<Sequence>(static_cast<std::shared_ptr<Ope>>(args)...);
}

template <typename... Args> std::shared_ptr<Ope> cho(Args &&...args) {
    return std::make_shared<PrioritizedChoice>(
        false, static_cast<std::shared_ptr<Ope>>(args)...);
}

template <typename... Args> std::shared_ptr<Ope> cho4label_(Args &&...args) {
    return std::make_shared<PrioritizedChoice>(
        true, static_cast<std::shared_ptr<Ope>>(args)...);
}

inline std::shared_ptr<Ope> zom(const std::shared_ptr<Ope> &ope) {
    return Repetition::zom(ope);
}

inline std::shared_ptr<Ope> oom(const std::shared_ptr<Ope> &ope) {
    return Repetition::oom(ope);
}

inline std::shared_ptr<Ope> opt(const std::shared_ptr<Ope> &ope) {
    return Repetition::opt(ope);
}

inline std::shared_ptr<Ope> rep(const std::shared_ptr<Ope> &ope, size_t min,
                                size_t max) {
    return std::make_shared<Repetition>(ope, min, max);
}

inline std::shared_ptr<Ope> apd(const std::shared_ptr<Ope> &ope) {
    return std::make_shared<AndPredicate>(ope);
}

inline std::shared_ptr<Ope> npd(const std::shared_ptr<Ope> &ope) {
    return std::make_shared<NotPredicate>(ope);
}

inline std::shared_ptr<Ope> dic(const std::vector<std::string> &v,
                                bool ignore_case) {
    return std::make_shared<Dictionary>(v, ignore_case);
}

inline std::shared_ptr<Ope> lit(std::string &&s) {
    return std::make_shared<LiteralString>(s, false);
}

inline std::shared_ptr<Ope> liti(std::string &&s) {
    return std::make_shared<LiteralString>(s, true);
}

inline std::shared_ptr<Ope> cls(const std::string &s) {
    return std::make_shared<CharacterClass>(s, false, false);
}

inline std::shared_ptr<Ope>
cls(const std::vector<std::pair<char32_t, char32_t>> &ranges,
    bool ignore_case = false) {
    return std::make_shared<CharacterClass>(ranges, false, ignore_case);
}

inline std::shared_ptr<Ope> ncls(const std::string &s) {
    return std::make_shared<CharacterClass>(s, true, false);
}

inline std::shared_ptr<Ope>
ncls(const std::vector<std::pair<char32_t, char32_t>> &ranges,
     bool ignore_case = false) {
    return std::make_shared<CharacterClass>(ranges, true, ignore_case);
}

inline std::shared_ptr<Ope> chr(char dt) {
    return std::make_shared<Character>(dt);
}

inline std::shared_ptr<Ope> dot() { return std::make_shared<AnyCharacter>(); }

inline std::shared_ptr<Ope> csc(const std::shared_ptr<Ope> &ope) {
    return std::make_shared<CaptureScope>(ope);
}

inline std::shared_ptr<Ope> cap(const std::shared_ptr<Ope> &ope,
                                Capture::MatchAction ma) {
    return std::make_shared<Capture>(ope, ma);
}

inline std::shared_ptr<Ope> tok(const std::shared_ptr<Ope> &ope) {
    return std::make_shared<TokenBoundary>(ope);
}

inline std::shared_ptr<Ope> ign(const std::shared_ptr<Ope> &ope) {
    return std::make_shared<Ignore>(ope);
}

inline std::shared_ptr<Ope>
usr(std::function<size_t(const char *s, size_t n, SemanticValues &vs,
                         std::any &dt)>
        fn) {
    return std::make_shared<User>(fn);
}

inline std::shared_ptr<Ope> ref(const Grammar &grammar, const std::string &name,
                                const char *s, bool is_macro,
                                const std::vector<std::shared_ptr<Ope>> &args) {
    return std::make_shared<Reference>(grammar, name, s, is_macro, args);
}

inline std::shared_ptr<Ope> wsp(const std::shared_ptr<Ope> &ope) {
    return std::make_shared<Whitespace>(std::make_shared<Ignore>(ope));
}

inline std::shared_ptr<Ope> bkr(std::string &&name) {
    return std::make_shared<BackReference>(name);
}

inline std::shared_ptr<Ope> pre(const std::shared_ptr<Ope> &atom,
                                const std::shared_ptr<Ope> &binop,
                                const PrecedenceClimbing::BinOpeInfo &info,
                                const Definition &rule) {
    return std::make_shared<PrecedenceClimbing>(atom, binop, info, rule);
}

inline std::shared_ptr<Ope> rec(const std::shared_ptr<Ope> &ope) {
    return std::make_shared<Recovery>(ope);
}

inline std::shared_ptr<Ope> cut() { return std::make_shared<Cut>(); }

/*
 * Visitor
 */
struct Ope::Visitor {
    virtual ~Visitor() {}
    virtual void visit(Sequence &) {}
    virtual void visit(PrioritizedChoice &) {}
    virtual void visit(Repetition &) {}
    virtual void visit(AndPredicate &) {}
    virtual void visit(NotPredicate &) {}
    virtual void visit(Dictionary &) {}
    virtual void visit(LiteralString &) {}
    virtual void visit(CharacterClass &) {}
    virtual void visit(Character &) {}
    virtual void visit(AnyCharacter &) {}
    virtual void visit(CaptureScope &) {}
    virtual void visit(Capture &) {}
    virtual void visit(TokenBoundary &) {}
    virtual void visit(Ignore &) {}
    virtual void visit(User &) {}
    virtual void visit(WeakHolder &) {}
    virtual void visit(Holder &) {}
    virtual void visit(Reference &) {}
    virtual void visit(Whitespace &) {}
    virtual void visit(BackReference &) {}
    virtual void visit(PrecedenceClimbing &) {}
    virtual void visit(Recovery &) {}
    virtual void visit(Cut &) {}
};

struct TraceOpeName : public Ope::Visitor {
    using Ope::Visitor::visit;

    void visit(Sequence &) override { name_ = "Sequence"; }
    void visit(PrioritizedChoice &) override { name_ = "PrioritizedChoice"; }
    void visit(Repetition &) override { name_ = "Repetition"; }
    void visit(AndPredicate &) override { name_ = "AndPredicate"; }
    void visit(NotPredicate &) override { name_ = "NotPredicate"; }
    void visit(Dictionary &) override { name_ = "Dictionary"; }
    void visit(LiteralString &) override { name_ = "LiteralString"; }
    void visit(CharacterClass &) override { name_ = "CharacterClass"; }
    void visit(Character &) override { name_ = "Character"; }
    void visit(AnyCharacter &) override { name_ = "AnyCharacter"; }
    void visit(CaptureScope &) override { name_ = "CaptureScope"; }
    void visit(Capture &) override { name_ = "Capture"; }
    void visit(TokenBoundary &) override { name_ = "TokenBoundary"; }
    void visit(Ignore &) override { name_ = "Ignore"; }
    void visit(User &) override { name_ = "User"; }
    void visit(WeakHolder &) override { name_ = "WeakHolder"; }
    void visit(Holder &ope) override { name_ = ope.trace_name().data(); }
    void visit(Reference &) override { name_ = "Reference"; }
    void visit(Whitespace &) override { name_ = "Whitespace"; }
    void visit(BackReference &) override { name_ = "BackReference"; }
    void visit(PrecedenceClimbing &) override { name_ = "PrecedenceClimbing"; }
    void visit(Recovery &) override { name_ = "Recovery"; }
    void visit(Cut &) override { name_ = "Cut"; }

    static std::string get(Ope &ope) {
        TraceOpeName vis;
        ope.accept(vis);
        return vis.name_;
    }

private:
    const char *name_ = nullptr;
};

struct AssignIDToDefinition : public Ope::Visitor {
    using Ope::Visitor::visit;

    void visit(Sequence &ope) override {
        for (auto op : ope.opes_) {
            op->accept(*this);
        }
    }
    void visit(PrioritizedChoice &ope) override {
        for (auto op : ope.opes_) {
            op->accept(*this);
        }
    }
    void visit(Repetition &ope) override { ope.ope_->accept(*this); }
    void visit(AndPredicate &ope) override { ope.ope_->accept(*this); }
    void visit(NotPredicate &ope) override { ope.ope_->accept(*this); }
    void visit(CaptureScope &ope) override { ope.ope_->accept(*this); }
    void visit(Capture &ope) override { ope.ope_->accept(*this); }
    void visit(TokenBoundary &ope) override { ope.ope_->accept(*this); }
    void visit(Ignore &ope) override { ope.ope_->accept(*this); }
    void visit(WeakHolder &ope) override { ope.weak_.lock()->accept(*this); }
    void visit(Holder &ope) override;
    void visit(Reference &ope) override;
    void visit(Whitespace &ope) override { ope.ope_->accept(*this); }
    void visit(PrecedenceClimbing &ope) override;
    void visit(Recovery &ope) override { ope.ope_->accept(*this); }

    std::unordered_map<void *, size_t> ids;
};

struct IsLiteralToken : public Ope::Visitor {
    using Ope::Visitor::visit;

    void visit(PrioritizedChoice &ope) override {
        for (auto op : ope.opes_) {
            if (!IsLiteralToken::check(*op)) { return; }
        }
        result_ = true;
    }

    void visit(Dictionary &) override { result_ = true; }
    void visit(LiteralString &) override { result_ = true; }

    static bool check(Ope &ope) {
        IsLiteralToken vis;
        ope.accept(vis);
        return vis.result_;
    }

private:
    bool result_ = false;
};

struct TokenChecker : public Ope::Visitor {
    using Ope::Visitor::visit;

    void visit(Sequence &ope) override {
        for (auto op : ope.opes_) {
            op->accept(*this);
        }
    }
    void visit(PrioritizedChoice &ope) override {
        for (auto op : ope.opes_) {
            op->accept(*this);
        }
    }
    void visit(Repetition &ope) override { ope.ope_->accept(*this); }
    void visit(CaptureScope &ope) override { ope.ope_->accept(*this); }
    void visit(Capture &ope) override { ope.ope_->accept(*this); }
    void visit(TokenBoundary &) override { has_token_boundary_ = true; }
    void visit(Ignore &ope) override { ope.ope_->accept(*this); }
    void visit(WeakHolder &) override { has_rule_ = true; }
    void visit(Holder &ope) override { ope.ope_->accept(*this); }
    void visit(Reference &ope) override;
    void visit(Whitespace &ope) override { ope.ope_->accept(*this); }
    void visit(PrecedenceClimbing &ope) override { ope.atom_->accept(*this); }
    void visit(Recovery &ope) override { ope.ope_->accept(*this); }

    static bool is_token(Ope &ope) {
        if (IsLiteralToken::check(ope)) { return true; }

        TokenChecker vis;
        ope.accept(vis);
        return vis.has_token_boundary_ || !vis.has_rule_;
    }

private:
    bool has_token_boundary_ = false;
    bool has_rule_ = false;
};

struct FindLiteralToken : public Ope::Visitor {
    using Ope::Visitor::visit;

    void visit(LiteralString &ope) override { token_ = ope.lit_.data(); }
    void visit(TokenBoundary &ope) override { ope.ope_->accept(*this); }
    void visit(Ignore &ope) override { ope.ope_->accept(*this); }
    void visit(Reference &ope) override;
    void visit(Recovery &ope) override { ope.ope_->accept(*this); }

    static const char *token(Ope &ope) {
        FindLiteralToken vis;
        ope.accept(vis);
        return vis.token_;
    }

private:
    const char *token_ = nullptr;
};

struct DetectLeftRecursion : public Ope::Visitor {
    using Ope::Visitor::visit;

    DetectLeftRecursion(const std::string &name) : name_(name) {}

    void visit(Sequence &ope) override {
        for (auto op : ope.opes_) {
            op->accept(*this);
            if (done_) {
                break;
            } else if (error_s) {
                done_ = true;
                break;
            }
        }
    }
    void visit(PrioritizedChoice &ope) override {
        for (auto op : ope.opes_) {
            op->accept(*this);
            if (error_s) {
                done_ = true;
                break;
            }
        }
    }
    void visit(Repetition &ope) override {
        ope.ope_->accept(*this);
        done_ = ope.min_ > 0;
    }
    void visit(AndPredicate &ope) override {
        ope.ope_->accept(*this);
        done_ = false;
    }
    void visit(NotPredicate &ope) override {
        ope.ope_->accept(*this);
        done_ = false;
    }
    void visit(Dictionary &) override { done_ = true; }
    void visit(LiteralString &ope) override { done_ = !ope.lit_.empty(); }
    void visit(CharacterClass &) override { done_ = true; }
    void visit(Character &) override { done_ = true; }
    void visit(AnyCharacter &) override { done_ = true; }
    void visit(CaptureScope &ope) override { ope.ope_->accept(*this); }
    void visit(Capture &ope) override { ope.ope_->accept(*this); }
    void visit(TokenBoundary &ope) override { ope.ope_->accept(*this); }
    void visit(Ignore &ope) override { ope.ope_->accept(*this); }
    void visit(User &) override { done_ = true; }
    void visit(WeakHolder &ope) override { ope.weak_.lock()->accept(*this); }
    void visit(Holder &ope) override { ope.ope_->accept(*this); }
    void visit(Reference &ope) override;
    void visit(Whitespace &ope) override { ope.ope_->accept(*this); }
    void visit(BackReference &) override { done_ = true; }
    void visit(PrecedenceClimbing &ope) override { ope.atom_->accept(*this); }
    void visit(Recovery &ope) override { ope.ope_->accept(*this); }
    void visit(Cut &) override { done_ = true; }

    const char *error_s = nullptr;

private:
    std::string name_;
    std::unordered_set<std::string> refs_;
    bool done_ = false;
};

struct HasEmptyElement : public Ope::Visitor {
    using Ope::Visitor::visit;

    HasEmptyElement(std::vector<std::pair<const char *, std::string>> &refs,
                    std::unordered_map<std::string, bool> &has_error_cache)
        : refs_(refs), has_error_cache_(has_error_cache) {}

    void visit(Sequence &ope) override;
    void visit(PrioritizedChoice &ope) override {
        for (auto op : ope.opes_) {
            op->accept(*this);
            if (is_empty) { return; }
        }
    }
    void visit(Repetition &ope) override {
        if (ope.min_ == 0) {
            set_error();
        } else {
            ope.ope_->accept(*this);
        }
    }
    void visit(AndPredicate &) override { set_error(); }
    void visit(NotPredicate &) override { set_error(); }
    void visit(LiteralString &ope) override {
        if (ope.lit_.empty()) { set_error(); }
    }
    void visit(CaptureScope &ope) override { ope.ope_->accept(*this); }
    void visit(Capture &ope) override { ope.ope_->accept(*this); }
    void visit(TokenBoundary &ope) override { ope.ope_->accept(*this); }
    void visit(Ignore &ope) override { ope.ope_->accept(*this); }
    void visit(WeakHolder &ope) override { ope.weak_.lock()->accept(*this); }
    void visit(Holder &ope) override { ope.ope_->accept(*this); }
    void visit(Reference &ope) override;
    void visit(Whitespace &ope) override { ope.ope_->accept(*this); }
    void visit(PrecedenceClimbing &ope) override { ope.atom_->accept(*this); }
    void visit(Recovery &ope) override { ope.ope_->accept(*this); }

    bool is_empty = false;
    const char *error_s = nullptr;
    std::string error_name;

private:
    void set_error() {
        is_empty = true;
        tie(error_s, error_name) = refs_.back();
    }
    std::vector<std::pair<const char *, std::string>> &refs_;
    std::unordered_map<std::string, bool> &has_error_cache_;
};

struct DetectInfiniteLoop : public Ope::Visitor {
    using Ope::Visitor::visit;

    DetectInfiniteLoop(const char *s, const std::string &name,
                       std::vector<std::pair<const char *, std::string>> &refs,
                       std::unordered_map<std::string, bool> &has_error_cache)
        : refs_(refs), has_error_cache_(has_error_cache) {
        refs_.emplace_back(s, name);
    }

    DetectInfiniteLoop(std::vector<std::pair<const char *, std::string>> &refs,
                       std::unordered_map<std::string, bool> &has_error_cache)
        : refs_(refs), has_error_cache_(has_error_cache) {}

    void visit(Sequence &ope) override {
        for (auto op : ope.opes_) {
            op->accept(*this);
            if (has_error) { return; }
        }
    }
    void visit(PrioritizedChoice &ope) override {
        for (auto op : ope.opes_) {
            op->accept(*this);
            if (has_error) { return; }
        }
    }
    void visit(Repetition &ope) override {
        if (ope.max_ == std::numeric_limits<size_t>::max()) {
            HasEmptyElement vis(refs_, has_error_cache_);
            ope.ope_->accept(vis);
            if (vis.is_empty) {
                has_error = true;
                error_s = vis.error_s;
                error_name = vis.error_name;
            }
        } else {
            ope.ope_->accept(*this);
        }
    }
    void visit(AndPredicate &ope) override { ope.ope_->accept(*this); }
    void visit(NotPredicate &ope) override { ope.ope_->accept(*this); }
    void visit(CaptureScope &ope) override { ope.ope_->accept(*this); }
    void visit(Capture &ope) override { ope.ope_->accept(*this); }
    void visit(TokenBoundary &ope) override { ope.ope_->accept(*this); }
    void visit(Ignore &ope) override { ope.ope_->accept(*this); }
    void visit(WeakHolder &ope) override { ope.weak_.lock()->accept(*this); }
    void visit(Holder &ope) override { ope.ope_->accept(*this); }
    void visit(Reference &ope) override;
    void visit(Whitespace &ope) override { ope.ope_->accept(*this); }
    void visit(PrecedenceClimbing &ope) override { ope.atom_->accept(*this); }
    void visit(Recovery &ope) override { ope.ope_->accept(*this); }

    bool has_error = false;
    const char *error_s = nullptr;
    std::string error_name;

private:
    std::vector<std::pair<const char *, std::string>> &refs_;
    std::unordered_map<std::string, bool> &has_error_cache_;
};

struct ReferenceChecker : public Ope::Visitor {
    using Ope::Visitor::visit;

    ReferenceChecker(const Grammar &grammar,
                     const std::vector<std::string> &params)
        : grammar_(grammar), params_(params) {}

    void visit(Sequence &ope) override {
        for (auto op : ope.opes_) {
            op->accept(*this);
        }
    }
    void visit(PrioritizedChoice &ope) override {
        for (auto op : ope.opes_) {
            op->accept(*this);
        }
    }
    void visit(Repetition &ope) override { ope.ope_->accept(*this); }
    void visit(AndPredicate &ope) override { ope.ope_->accept(*this); }
    void visit(NotPredicate &ope) override { ope.ope_->accept(*this); }
    void visit(CaptureScope &ope) override { ope.ope_->accept(*this); }
    void visit(Capture &ope) override { ope.ope_->accept(*this); }
    void visit(TokenBoundary &ope) override { ope.ope_->accept(*this); }
    void visit(Ignore &ope) override { ope.ope_->accept(*this); }
    void visit(WeakHolder &ope) override { ope.weak_.lock()->accept(*this); }
    void visit(Holder &ope) override { ope.ope_->accept(*this); }
    void visit(Reference &ope) override;
    void visit(Whitespace &ope) override { ope.ope_->accept(*this); }
    void visit(PrecedenceClimbing &ope) override { ope.atom_->accept(*this); }
    void visit(Recovery &ope) override { ope.ope_->accept(*this); }

    std::unordered_map<std::string, const char *> error_s;
    std::unordered_map<std::string, std::string> error_message;
    std::unordered_set<std::string> referenced;

private:
    const Grammar &grammar_;
    const std::vector<std::string> &params_;
};

struct LinkReferences : public Ope::Visitor {
    using Ope::Visitor::visit;

    LinkReferences(Grammar &grammar, const std::vector<std::string> &params)
        : grammar_(grammar), params_(params) {}

    void visit(Sequence &ope) override {
        for (auto op : ope.opes_) {
            op->accept(*this);
        }
    }
    void visit(PrioritizedChoice &ope) override {
        for (auto op : ope.opes_) {
            op->accept(*this);
        }
    }
    void visit(Repetition &ope) override { ope.ope_->accept(*this); }
    void visit(AndPredicate &ope) override { ope.ope_->accept(*this); }
    void visit(NotPredicate &ope) override { ope.ope_->accept(*this); }
    void visit(CaptureScope &ope) override { ope.ope_->accept(*this); }
    void visit(Capture &ope) override { ope.ope_->accept(*this); }
    void visit(TokenBoundary &ope) override { ope.ope_->accept(*this); }
    void visit(Ignore &ope) override { ope.ope_->accept(*this); }
    void visit(WeakHolder &ope) override { ope.weak_.lock()->accept(*this); }
    void visit(Holder &ope) override { ope.ope_->accept(*this); }
    void visit(Reference &ope) override;
    void visit(Whitespace &ope) override { ope.ope_->accept(*this); }
    void visit(PrecedenceClimbing &ope) override { ope.atom_->accept(*this); }
    void visit(Recovery &ope) override { ope.ope_->accept(*this); }

private:
    Grammar &grammar_;
    const std::vector<std::string> &params_;
};

struct FindReference : public Ope::Visitor {
    using Ope::Visitor::visit;

    FindReference(const std::vector<std::shared_ptr<Ope>> &args,
                  const std::vector<std::string> &params)
        : args_(args), params_(params) {}

    void visit(Sequence &ope) override {
        std::vector<std::shared_ptr<Ope>> opes;
        for (auto o : ope.opes_) {
            o->accept(*this);
            opes.push_back(found_ope);
        }
        found_ope = std::make_shared<Sequence>(opes);
    }
    void visit(PrioritizedChoice &ope) override {
        std::vector<std::shared_ptr<Ope>> opes;
        for (auto o : ope.opes_) {
            o->accept(*this);
            opes.push_back(found_ope);
        }
        found_ope = std::make_shared<PrioritizedChoice>(opes);
    }
    void visit(Repetition &ope) override {
        ope.ope_->accept(*this);
        found_ope = rep(found_ope, ope.min_, ope.max_);
    }
    void visit(AndPredicate &ope) override {
        ope.ope_->accept(*this);
        found_ope = apd(found_ope);
    }
    void visit(NotPredicate &ope) override {
        ope.ope_->accept(*this);
        found_ope = npd(found_ope);
    }
    void visit(Dictionary &ope) override { found_ope = ope.shared_from_this(); }
    void visit(LiteralString &ope) override {
        found_ope = ope.shared_from_this();
    }
    void visit(CharacterClass &ope) override {
        found_ope = ope.shared_from_this();
    }
    void visit(Character &ope) override { found_ope = ope.shared_from_this(); }
    void visit(AnyCharacter &ope) override { found_ope = ope.shared_from_this(); }
    void visit(CaptureScope &ope) override {
        ope.ope_->accept(*this);
        found_ope = csc(found_ope);
    }
    void visit(Capture &ope) override {
        ope.ope_->accept(*this);
        found_ope = cap(found_ope, ope.match_action_);
    }
    void visit(TokenBoundary &ope) override {
        ope.ope_->accept(*this);
        found_ope = tok(found_ope);
    }
    void visit(Ignore &ope) override {
        ope.ope_->accept(*this);
        found_ope = ign(found_ope);
    }
    void visit(WeakHolder &ope) override { ope.weak_.lock()->accept(*this); }
    void visit(Holder &ope) override { ope.ope_->accept(*this); }
    void visit(Reference &ope) override;
    void visit(Whitespace &ope) override {
        ope.ope_->accept(*this);
        found_ope = wsp(found_ope);
    }
    void visit(PrecedenceClimbing &ope) override {
        ope.atom_->accept(*this);
        found_ope = csc(found_ope);
    }
    void visit(Recovery &ope) override {
        ope.ope_->accept(*this);
        found_ope = rec(found_ope);
    }
    void visit(Cut &ope) override { found_ope = ope.shared_from_this(); }

    std::shared_ptr<Ope> found_ope;

private:
    const std::vector<std::shared_ptr<Ope>> &args_;
    const std::vector<std::string> &params_;
};

/*
 * Keywords
 */
static const char *WHITESPACE_DEFINITION_NAME = "%whitespace";
static const char *WORD_DEFINITION_NAME = "%word";
static const char *RECOVER_DEFINITION_NAME = "%recover";

/*
 * Definition
 */
class Definition {
public:
    struct Result {
        bool ret;
        bool recovered;
        size_t len;
        ErrorInfo error_info;
    };

    Definition() : holder_(std::make_shared<Holder>(this)) {}

    Definition(const Definition &rhs) : name(rhs.name), holder_(rhs.holder_) {
        holder_->outer_ = this;
    }

    Definition(const std::shared_ptr<Ope> &ope)
        : holder_(std::make_shared<Holder>(this)) {
        *this <= ope;
    }

    operator std::shared_ptr<Ope>() {
        return std::make_shared<WeakHolder>(holder_);
    }

    Definition &operator<=(const std::shared_ptr<Ope> &ope) {
        holder_->ope_ = ope;
        return *this;
    }

    Result parse(const char *s, size_t n, const char *path = nullptr,
                 Log log = nullptr) const {
        SemanticValues vs;
        std::any dt;
        return parse_core(s, n, vs, dt, path, log);
    }

    Result parse(const char *s, const char *path = nullptr,
                 Log log = nullptr) const {
        auto n = strlen(s);
        return parse(s, n, path, log);
    }

    Result parse(const char *s, size_t n, std::any &dt,
                 const char *path = nullptr, Log log = nullptr) const {
        SemanticValues vs;
        return parse_core(s, n, vs, dt, path, log);
    }

    Result parse(const char *s, std::any &dt, const char *path = nullptr,
                 Log log = nullptr) const {
        auto n = strlen(s);
        return parse(s, n, dt, path, log);
    }

    template <typename T>
    Result parse_and_get_value(const char *s, size_t n, T &val,
                               const char *path = nullptr,
                               Log log = nullptr) const {
        SemanticValues vs;
        std::any dt;
        auto r = parse_core(s, n, vs, dt, path, log);
        if (r.ret && !vs.empty() && vs.front().has_value()) {
            val = std::any_cast<T>(vs[0]);
        }
        return r;
    }

    template <typename T>
    Result parse_and_get_value(const char *s, T &val, const char *path = nullptr,
                               Log log = nullptr) const {
        auto n = strlen(s);
        return parse_and_get_value(s, n, val, path, log);
    }

    template <typename T>
    Result parse_and_get_value(const char *s, size_t n, std::any &dt, T &val,
                               const char *path = nullptr,
                               Log log = nullptr) const {
        SemanticValues vs;
        auto r = parse_core(s, n, vs, dt, path, log);
        if (r.ret && !vs.empty() && vs.front().has_value()) {
            val = std::any_cast<T>(vs[0]);
        }
        return r;
    }

    template <typename T>
    Result parse_and_get_value(const char *s, std::any &dt, T &val,
                               const char *path = nullptr,
                               Log log = nullptr) const {
        auto n = strlen(s);
        return parse_and_get_value(s, n, dt, val, path, log);
    }

#if defined(__cpp_lib_char8_t)
    Result parse(const char8_t *s, size_t n, const char *path = nullptr,
                 Log log = nullptr) const {
        return parse(reinterpret_cast<const char *>(s), n, path, log);
    }

    Result parse(const char8_t *s, const char *path = nullptr,
                 Log log = nullptr) const {
        return parse(reinterpret_cast<const char *>(s), path, log);
    }

    Result parse(const char8_t *s, size_t n, std::any &dt,
                 const char *path = nullptr, Log log = nullptr) const {
        return parse(reinterpret_cast<const char *>(s), n, dt, path, log);
    }

    Result parse(const char8_t *s, std::any &dt, const char *path = nullptr,
                 Log log = nullptr) const {
        return parse(reinterpret_cast<const char *>(s), dt, path, log);
    }

    template <typename T>
    Result parse_and_get_value(const char8_t *s, size_t n, T &val,
                               const char *path = nullptr,
                               Log log = nullptr) const {
        return parse_and_get_value(reinterpret_cast<const char *>(s), n, val, *path,
                                   log);
    }

    template <typename T>
    Result parse_and_get_value(const char8_t *s, T &val,
                               const char *path = nullptr,
                               Log log = nullptr) const {
        return parse_and_get_value(reinterpret_cast<const char *>(s), val, *path,
                                   log);
    }

    template <typename T>
    Result parse_and_get_value(const char8_t *s, size_t n, std::any &dt, T &val,
                               const char *path = nullptr,
                               Log log = nullptr) const {
        return parse_and_get_value(reinterpret_cast<const char *>(s), n, dt, val,
                                   *path, log);
    }

    template <typename T>
    Result parse_and_get_value(const char8_t *s, std::any &dt, T &val,
                               const char *path = nullptr,
                               Log log = nullptr) const {
        return parse_and_get_value(reinterpret_cast<const char *>(s), dt, val,
                                   *path, log);
    }
#endif

    void operator=(Action a) { action = a; }

    template <typename T> Definition &operator,(T fn) {
        operator=(fn);
        return *this;
    }

    Definition &operator~() {
        ignoreSemanticValue = true;
        return *this;
    }

    void accept(Ope::Visitor &v) { holder_->accept(v); }

    std::shared_ptr<Ope> get_core_operator() const { return holder_->ope_; }

    bool is_token() const {
        std::call_once(is_token_init_, [this]() {
            is_token_ = TokenChecker::is_token(*get_core_operator());
        });
        return is_token_;
    }

    std::string name;
    const char *s_ = nullptr;
    std::pair<size_t, size_t> line_ = {1, 1};

    std::function<bool(const SemanticValues &vs, const std::any &dt,
                       std::string &msg)>
        predicate;

    size_t id = 0;
    Action action;
    std::function<void(const Context &c, const char *s, size_t n, std::any &dt)>
        enter;
    std::function<void(const Context &c, const char *s, size_t n, size_t matchlen,
                       std::any &value, std::any &dt)>
        leave;
    bool ignoreSemanticValue = false;
    std::shared_ptr<Ope> whitespaceOpe;
    std::shared_ptr<Ope> wordOpe;
    bool enablePackratParsing = false;
    bool is_macro = false;
    std::vector<std::string> params;
    bool disable_action = false;

    TracerEnter tracer_enter;
    TracerLeave tracer_leave;
    bool verbose_trace = false;
    TracerStartOrEnd tracer_start;
    TracerStartOrEnd tracer_end;

    std::string error_message;
    bool no_ast_opt = false;

    bool eoi_check = true;

private:
    friend class Reference;
    friend class ParserGenerator;

    Definition &operator=(const Definition &rhs);
    Definition &operator=(Definition &&rhs);

    void initialize_definition_ids() const {
        std::call_once(definition_ids_init_, [&]() {
            AssignIDToDefinition vis;
            holder_->accept(vis);
            if (whitespaceOpe) { whitespaceOpe->accept(vis); }
            if (wordOpe) { wordOpe->accept(vis); }
            definition_ids_.swap(vis.ids);
        });
    }

    Result parse_core(const char *s, size_t n, SemanticValues &vs, std::any &dt,
                      const char *path, Log log) const {
        initialize_definition_ids();

        std::shared_ptr<Ope> ope = holder_;

        std::any trace_data;
        if (tracer_start) { tracer_start(trace_data); }
        auto se1 = scope_exit([&]() {
            if (tracer_end) { tracer_end(trace_data); }
        });

        Context c(path, s, n, definition_ids_.size(), whitespaceOpe, wordOpe,
                  enablePackratParsing, tracer_enter, tracer_leave, trace_data,
                  verbose_trace, log);

        size_t i = 0;

        if (whitespaceOpe) {
            auto save_ignore_trace_state = c.ignore_trace_state;
            c.ignore_trace_state = !c.verbose_trace;
            auto se2 =
                scope_exit([&]() { c.ignore_trace_state = save_ignore_trace_state; });

            auto len = whitespaceOpe->parse(s, n, vs, c, dt);
            if (fail(len)) { return Result{false, c.recovered, i, c.error_info}; }

            i = len;
        }

        auto len = ope->parse(s + i, n - i, vs, c, dt);
        auto ret = success(len);
        if (ret) {
            i += len;
            if (eoi_check) {
                if (i < n) {
                    if (c.error_info.error_pos - c.s < s + i - c.s) {
                        c.error_info.message_pos = s + i;
                        c.error_info.message = "expected end of input";
                    }
                    ret = false;
                }
            }
        }
        return Result{ret, c.recovered, i, c.error_info};
    }

    std::shared_ptr<Holder> holder_;
    mutable std::once_flag is_token_init_;
    mutable bool is_token_ = false;
    mutable std::once_flag assign_id_to_definition_init_;
    mutable std::once_flag definition_ids_init_;
    mutable std::unordered_map<void *, size_t> definition_ids_;
};

/*
 * Implementations
 */

inline size_t parse_literal(const char *s, size_t n, SemanticValues &vs,
                            Context &c, std::any &dt, const std::string &lit,
                            std::once_flag &init_is_word, bool &is_word,
                            bool ignore_case) {
    size_t i = 0;
    for (; i < lit.size(); i++) {
        if (i >= n || (ignore_case ? (std::tolower(s[i]) != std::tolower(lit[i]))
                                   : (s[i] != lit[i]))) {
            c.set_error_pos(s, lit.data());
            return static_cast<size_t>(-1);
        }
    }

    // Word check
    if (c.wordOpe) {
        auto save_ignore_trace_state = c.ignore_trace_state;
        c.ignore_trace_state = !c.verbose_trace;
        auto se =
            scope_exit([&]() { c.ignore_trace_state = save_ignore_trace_state; });

        std::call_once(init_is_word, [&]() {
            SemanticValues dummy_vs;
            Context dummy_c(nullptr, c.s, c.l, 0, nullptr, nullptr, false, nullptr,
                            nullptr, nullptr, false, nullptr);
            std::any dummy_dt;

            auto len =
                c.wordOpe->parse(lit.data(), lit.size(), dummy_vs, dummy_c, dummy_dt);
            is_word = success(len);
        });

        if (is_word) {
            SemanticValues dummy_vs;
            Context dummy_c(nullptr, c.s, c.l, 0, nullptr, nullptr, false, nullptr,
                            nullptr, nullptr, false, nullptr);
            std::any dummy_dt;

            NotPredicate ope(c.wordOpe);
            auto len = ope.parse(s + i, n - i, dummy_vs, dummy_c, dummy_dt);
            if (fail(len)) {
                c.set_error_pos(s, lit.data());
                return len;
            }
            i += len;
        }
    }

    // Skip whitespace
    if (!c.in_token_boundary_count && c.whitespaceOpe) {
        auto save_ignore_trace_state = c.ignore_trace_state;
        c.ignore_trace_state = !c.verbose_trace;
        auto se =
            scope_exit([&]() { c.ignore_trace_state = save_ignore_trace_state; });

        auto len = c.whitespaceOpe->parse(s + i, n - i, vs, c, dt);
        if (fail(len)) { return len; }
        i += len;
    }

    return i;
}

inline std::pair<size_t, size_t> SemanticValues::line_info() const {
    assert(c_);
    return c_->line_info(sv_.data());
}

inline void ErrorInfo::output_log(const Log &log, const char *s, size_t n) {
    if (message_pos) {
        if (message_pos > last_output_pos) {
            last_output_pos = message_pos;
            auto line = line_info(s, message_pos);
            std::string msg;
            if (auto unexpected_token = heuristic_error_token(s, n, message_pos);
                !unexpected_token.empty()) {
                msg = replace_all(message, "%t", unexpected_token);

                auto unexpected_char = unexpected_token.substr(
                    0,
                    codepoint_length(unexpected_token.data(), unexpected_token.size()));

                msg = replace_all(msg, "%c", unexpected_char);
            } else {
                msg = message;
            }
            log(line.first, line.second, msg, label);
        }
    } else if (error_pos) {
        if (error_pos > last_output_pos) {
            last_output_pos = error_pos;
            auto line = line_info(s, error_pos);

            std::string msg;
            if (expected_tokens.empty()) {
                msg = "syntax error.";
            } else {
                msg = "syntax error";

                // unexpected token
                if (auto unexpected_token = heuristic_error_token(s, n, error_pos);
                    !unexpected_token.empty()) {
                    msg += ", unexpected '";
                    msg += unexpected_token;
                    msg += "'";
                }

                auto first_item = true;
                size_t i = 0;
                while (i < expected_tokens.size()) {
                    auto [error_literal, error_rule] = expected_tokens[i];

                    // Skip rules start with '_'
                    if (!(error_rule && error_rule->name[0] == '_')) {
                        msg += (first_item ? ", expecting " : ", ");
                        if (error_literal) {
                            msg += "'";
                            msg += error_literal;
                            msg += "'";
                        } else {
                            msg += "<" + error_rule->name + ">";
                            if (label.empty()) { label = error_rule->name; }
                        }
                        first_item = false;
                    }

                    i++;
                }
                msg += ".";
            }
            log(line.first, line.second, msg, label);
        }
    }
}

inline void Context::set_error_pos(const char *a_s, const char *literal) {
    if (log) {
        if (error_info.error_pos <= a_s) {
            if (error_info.error_pos < a_s || !error_info.keep_previous_token) {
                error_info.error_pos = a_s;
                error_info.expected_tokens.clear();
            }

            const char *error_literal = nullptr;
            const Definition *error_rule = nullptr;

            if (literal) {
                error_literal = literal;
            } else if (!rule_stack.empty()) {
                auto rule = rule_stack.back();
                auto ope = rule->get_core_operator();
                if (auto token = FindLiteralToken::token(*ope);
                    token && token[0] != '\0') {
                    error_literal = token;
                }
            }

            for (auto r : rule_stack) {
                error_rule = r;
                if (r->is_token()) { break; }
            }

            if (error_literal || error_rule) {
                error_info.add(error_literal, error_rule);
            }
        }
    }
}

inline void Context::trace_enter(const Ope &ope, const char *a_s, size_t n,
                                 const SemanticValues &vs, std::any &dt) {
    trace_ids.push_back(next_trace_id++);
    tracer_enter(ope, a_s, n, vs, *this, dt, trace_data);
}

inline void Context::trace_leave(const Ope &ope, const char *a_s, size_t n,
                                 const SemanticValues &vs, std::any &dt,
                                 size_t len) {
    tracer_leave(ope, a_s, n, vs, *this, dt, len, trace_data);
    trace_ids.pop_back();
}

inline bool Context::is_traceable(const Ope &ope) const {
    if (tracer_enter && tracer_leave) {
        if (ignore_trace_state) { return false; }
        return !dynamic_cast<const peg::Reference *>(&ope);
    }
    return false;
}

inline size_t Ope::parse(const char *s, size_t n, SemanticValues &vs,
                         Context &c, std::any &dt) const {
    if (c.is_traceable(*this)) {
        c.trace_enter(*this, s, n, vs, dt);
        auto len = parse_core(s, n, vs, c, dt);
        c.trace_leave(*this, s, n, vs, dt, len);
        return len;
    }
    return parse_core(s, n, vs, c, dt);
}

inline size_t Dictionary::parse_core(const char *s, size_t n,
                                     SemanticValues &vs, Context &c,
                                     std::any &dt) const {
    size_t id;
    auto i = trie_.match(s, n, id);

    if (i == 0) {
        c.set_error_pos(s);
        return static_cast<size_t>(-1);
    }

    vs.choice_count_ = trie_.size();
    vs.choice_ = id;

    // Word check
    if (c.wordOpe) {
        auto save_ignore_trace_state = c.ignore_trace_state;
        c.ignore_trace_state = !c.verbose_trace;
        auto se =
            scope_exit([&]() { c.ignore_trace_state = save_ignore_trace_state; });

        {
            SemanticValues dummy_vs;
            Context dummy_c(nullptr, c.s, c.l, 0, nullptr, nullptr, false, nullptr,
                            nullptr, nullptr, false, nullptr);
            std::any dummy_dt;

            NotPredicate ope(c.wordOpe);
            auto len = ope.parse(s + i, n - i, dummy_vs, dummy_c, dummy_dt);
            if (fail(len)) {
                c.set_error_pos(s);
                return len;
            }
            i += len;
        }
    }

    // Skip whitespace
    if (!c.in_token_boundary_count && c.whitespaceOpe) {
        auto save_ignore_trace_state = c.ignore_trace_state;
        c.ignore_trace_state = !c.verbose_trace;
        auto se =
            scope_exit([&]() { c.ignore_trace_state = save_ignore_trace_state; });

        auto len = c.whitespaceOpe->parse(s + i, n - i, vs, c, dt);
        if (fail(len)) { return len; }
        i += len;
    }

    return i;
}

inline size_t LiteralString::parse_core(const char *s, size_t n,
                                        SemanticValues &vs, Context &c,
                                        std::any &dt) const {
    return parse_literal(s, n, vs, c, dt, lit_, init_is_word_, is_word_,
                         ignore_case_);
}

inline size_t TokenBoundary::parse_core(const char *s, size_t n,
                                        SemanticValues &vs, Context &c,
                                        std::any &dt) const {
    auto save_ignore_trace_state = c.ignore_trace_state;
    c.ignore_trace_state = !c.verbose_trace;
    auto se1 =
        scope_exit([&]() { c.ignore_trace_state = save_ignore_trace_state; });

    size_t len;
    {
        c.in_token_boundary_count++;
        auto se2 = scope_exit([&]() { c.in_token_boundary_count--; });
        len = ope_->parse(s, n, vs, c, dt);
    }

    if (success(len)) {
        vs.tokens.emplace_back(std::string_view(s, len));

        if (!c.in_token_boundary_count) {
            if (c.whitespaceOpe) {
                auto l = c.whitespaceOpe->parse(s + len, n - len, vs, c, dt);
                if (fail(l)) { return l; }
                len += l;
            }
        }
    }
    return len;
}

inline size_t Holder::parse_core(const char *s, size_t n, SemanticValues &vs,
                                 Context &c, std::any &dt) const {
    if (!ope_) {
        throw std::logic_error("Uninitialized definition ope was used...");
    }

    // Macro reference
    if (outer_->is_macro) {
        c.rule_stack.push_back(outer_);
        auto len = ope_->parse(s, n, vs, c, dt);
        c.rule_stack.pop_back();
        return len;
    }

    size_t len;
    std::any val;

    c.packrat(s, outer_->id, len, val, [&](std::any &a_val) {
        if (outer_->enter) { outer_->enter(c, s, n, dt); }
        auto &chvs = c.push_semantic_values_scope();
        auto se = scope_exit([&]() {
            c.pop_semantic_values_scope();
            if (outer_->leave) { outer_->leave(c, s, n, len, a_val, dt); }
        });

        c.rule_stack.push_back(outer_);
        len = ope_->parse(s, n, chvs, c, dt);
        c.rule_stack.pop_back();

        // Invoke action
        if (success(len)) {
            chvs.sv_ = std::string_view(s, len);
            chvs.name_ = outer_->name;

            auto ope_ptr = ope_.get();
            {
                auto tok_ptr = dynamic_cast<const peg::TokenBoundary *>(ope_ptr);
                if (tok_ptr) { ope_ptr = tok_ptr->ope_.get(); }
            }
            if (!dynamic_cast<const peg::PrioritizedChoice *>(ope_ptr) &&
                !dynamic_cast<const peg::Dictionary *>(ope_ptr)) {
                chvs.choice_count_ = 0;
                chvs.choice_ = 0;
            }

            std::string msg;
            if (outer_->predicate && !outer_->predicate(chvs, dt, msg)) {
                if (c.log && !msg.empty() && c.error_info.message_pos < s) {
                    c.error_info.message_pos = s;
                    c.error_info.message = msg;
                    c.error_info.label = outer_->name;
                }
                len = static_cast<size_t>(-1);
            }

            if (success(len)) {
                if (!c.recovered) { a_val = reduce(chvs, dt); }
            } else {
                if (c.log && !msg.empty() && c.error_info.message_pos < s) {
                    c.error_info.message_pos = s;
                    c.error_info.message = msg;
                    c.error_info.label = outer_->name;
                }
            }
        } else {
            if (c.log && !outer_->error_message.empty() &&
                c.error_info.message_pos < s) {
                c.error_info.message_pos = s;
                c.error_info.message = outer_->error_message;
                c.error_info.label = outer_->name;
            }
        }
    });

    if (success(len)) {
        if (!outer_->ignoreSemanticValue) {
            vs.emplace_back(std::move(val));
            vs.tags.emplace_back(str2tag(outer_->name));
        }
    }

    return len;
}

inline std::any Holder::reduce(SemanticValues &vs, std::any &dt) const {
    if (outer_->action && !outer_->disable_action) {
        return outer_->action(vs, dt);
    } else if (vs.empty()) {
        return std::any();
    } else {
        return std::move(vs.front());
    }
}

inline const std::string &Holder::name() const { return outer_->name; }

inline const std::string &Holder::trace_name() const {
    std::call_once(trace_name_init_,
                   [this]() { trace_name_ = "[" + outer_->name + "]"; });
    return trace_name_;
}

inline size_t Reference::parse_core(const char *s, size_t n, SemanticValues &vs,
                                    Context &c, std::any &dt) const {
    auto save_ignore_trace_state = c.ignore_trace_state;
    if (rule_ && rule_->ignoreSemanticValue) {
        c.ignore_trace_state = !c.verbose_trace;
    }
    auto se1 =
        scope_exit([&]() { c.ignore_trace_state = save_ignore_trace_state; });

    if (rule_) {
        // Reference rule
        if (rule_->is_macro) {
            // Macro
            FindReference vis(c.top_args(), c.rule_stack.back()->params);

            // Collect arguments
            std::vector<std::shared_ptr<Ope>> args;
            for (auto arg : args_) {
                arg->accept(vis);
                args.emplace_back(std::move(vis.found_ope));
            }

            c.push_args(std::move(args));
            auto se2 = scope_exit([&]() { c.pop_args(); });
            auto ope = get_core_operator();
            return ope->parse(s, n, vs, c, dt);
        } else {
            // Definition
            c.push_args(std::vector<std::shared_ptr<Ope>>());
            auto se3 = scope_exit([&]() { c.pop_args(); });
            auto ope = get_core_operator();
            return ope->parse(s, n, vs, c, dt);
        }
    } else {
        // Reference parameter in macro
        const auto &args = c.top_args();
        return args[iarg_]->parse(s, n, vs, c, dt);
    }
}

inline std::shared_ptr<Ope> Reference::get_core_operator() const {
    return rule_->holder_;
}

inline size_t BackReference::parse_core(const char *s, size_t n,
                                        SemanticValues &vs, Context &c,
                                        std::any &dt) const {
    auto size = static_cast<int>(c.capture_scope_stack_size);
    for (auto i = size - 1; i >= 0; i--) {
        auto index = static_cast<size_t>(i);
        const auto &cs = c.capture_scope_stack[index];
        if (cs.find(name_) != cs.end()) {
            const auto &lit = cs.at(name_);
            std::once_flag init_is_word;
            auto is_word = false;
            return parse_literal(s, n, vs, c, dt, lit, init_is_word, is_word, false);
        }
    }

    c.error_info.message_pos = s;
    c.error_info.message = "undefined back reference '$" + name_ + "'...";
    return static_cast<size_t>(-1);
}

inline Definition &
PrecedenceClimbing::get_reference_for_binop(Context &c) const {
    if (rule_.is_macro) {
        // Reference parameter in macro
        const auto &args = c.top_args();
        auto iarg = dynamic_cast<Reference &>(*binop_).iarg_;
        auto arg = args[iarg];
        return *dynamic_cast<Reference &>(*arg).rule_;
    }

    return *dynamic_cast<Reference &>(*binop_).rule_;
}

inline size_t PrecedenceClimbing::parse_expression(const char *s, size_t n,
                                                   SemanticValues &vs,
                                                   Context &c, std::any &dt,
                                                   size_t min_prec) const {
    auto len = atom_->parse(s, n, vs, c, dt);
    if (fail(len)) { return len; }

    std::string tok;
    auto &rule = get_reference_for_binop(c);
    auto action = std::move(rule.action);

    rule.action = [&](SemanticValues &vs2, std::any &dt2) {
        tok = vs2.token();
        if (action) {
            return action(vs2, dt2);
        } else if (!vs2.empty()) {
            return vs2[0];
        }
        return std::any();
    };
    auto action_se = scope_exit([&]() { rule.action = std::move(action); });

    auto i = len;
    while (i < n) {
        std::vector<std::any> save_values(vs.begin(), vs.end());
        auto save_tokens = vs.tokens;

        auto chvs = c.push_semantic_values_scope();
        auto chlen = binop_->parse(s + i, n - i, chvs, c, dt);
        c.pop_semantic_values_scope();

        if (fail(chlen)) { break; }

        auto it = info_.find(tok);
        if (it == info_.end()) { break; }

        auto level = std::get<0>(it->second);
        auto assoc = std::get<1>(it->second);

        if (level < min_prec) { break; }

        vs.emplace_back(std::move(chvs[0]));
        i += chlen;

        auto next_min_prec = level;
        if (assoc == 'L') { next_min_prec = level + 1; }

        chvs = c.push_semantic_values_scope();
        chlen = parse_expression(s + i, n - i, chvs, c, dt, next_min_prec);
        c.pop_semantic_values_scope();

        if (fail(chlen)) {
            vs.assign(save_values.begin(), save_values.end());
            vs.tokens = save_tokens;
            i = chlen;
            break;
        }

        vs.emplace_back(std::move(chvs[0]));
        i += chlen;

        std::any val;
        if (rule_.action) {
            vs.sv_ = std::string_view(s, i);
            val = rule_.action(vs, dt);
        } else if (!vs.empty()) {
            val = vs[0];
        }
        vs.clear();
        vs.emplace_back(std::move(val));
    }

    return i;
}

inline size_t Recovery::parse_core(const char *s, size_t n,
                                   SemanticValues & /*vs*/, Context &c,
                                   std::any & /*dt*/) const {
    const auto &rule = dynamic_cast<Reference &>(*ope_);

    // Custom error message
    if (c.log) {
        auto label = dynamic_cast<Reference *>(rule.args_[0].get());
        if (label && !label->rule_->error_message.empty()) {
            c.error_info.message_pos = s;
            c.error_info.message = label->rule_->error_message;
            c.error_info.label = label->rule_->name;
        }
    }

    // Recovery
    auto len = static_cast<size_t>(-1);
    {
        auto save_log = c.log;
        c.log = nullptr;
        auto se = scope_exit([&]() { c.log = save_log; });

        SemanticValues dummy_vs;
        std::any dummy_dt;

        len = rule.parse(s, n, dummy_vs, c, dummy_dt);
    }

    if (success(len)) {
        c.recovered = true;

        if (c.log) {
            c.error_info.output_log(c.log, c.s, c.l);
            c.error_info.clear();
        }
    }

    // Cut
    if (!c.cut_stack.empty()) {
        c.cut_stack.back() = true;

        if (c.cut_stack.size() == 1) {
            // TODO: Remove unneeded entries in packrat memoise table
        }
    }

    return len;
}

inline void Sequence::accept(Visitor &v) { v.visit(*this); }
inline void PrioritizedChoice::accept(Visitor &v) { v.visit(*this); }
inline void Repetition::accept(Visitor &v) { v.visit(*this); }
inline void AndPredicate::accept(Visitor &v) { v.visit(*this); }
inline void NotPredicate::accept(Visitor &v) { v.visit(*this); }
inline void Dictionary::accept(Visitor &v) { v.visit(*this); }
inline void LiteralString::accept(Visitor &v) { v.visit(*this); }
inline void CharacterClass::accept(Visitor &v) { v.visit(*this); }
inline void Character::accept(Visitor &v) { v.visit(*this); }
inline void AnyCharacter::accept(Visitor &v) { v.visit(*this); }
inline void CaptureScope::accept(Visitor &v) { v.visit(*this); }
inline void Capture::accept(Visitor &v) { v.visit(*this); }
inline void TokenBoundary::accept(Visitor &v) { v.visit(*this); }
inline void Ignore::accept(Visitor &v) { v.visit(*this); }
inline void User::accept(Visitor &v) { v.visit(*this); }
inline void WeakHolder::accept(Visitor &v) { v.visit(*this); }
inline void Holder::accept(Visitor &v) { v.visit(*this); }
inline void Reference::accept(Visitor &v) { v.visit(*this); }
inline void Whitespace::accept(Visitor &v) { v.visit(*this); }
inline void BackReference::accept(Visitor &v) { v.visit(*this); }
inline void PrecedenceClimbing::accept(Visitor &v) { v.visit(*this); }
inline void Recovery::accept(Visitor &v) { v.visit(*this); }
inline void Cut::accept(Visitor &v) { v.visit(*this); }

inline void AssignIDToDefinition::visit(Holder &ope) {
    auto p = static_cast<void *>(ope.outer_);
    if (ids.count(p)) { return; }
    auto id = ids.size();
    ids[p] = id;
    ope.outer_->id = id;
    ope.ope_->accept(*this);
}

inline void AssignIDToDefinition::visit(Reference &ope) {
    if (ope.rule_) {
        for (auto arg : ope.args_) {
            arg->accept(*this);
        }
        ope.rule_->accept(*this);
    }
}

inline void AssignIDToDefinition::visit(PrecedenceClimbing &ope) {
    ope.atom_->accept(*this);
    ope.binop_->accept(*this);
}

inline void TokenChecker::visit(Reference &ope) {
    if (ope.is_macro_) {
        for (auto arg : ope.args_) {
            arg->accept(*this);
        }
    } else {
        has_rule_ = true;
    }
}

inline void FindLiteralToken::visit(Reference &ope) {
    if (ope.is_macro_) {
        ope.rule_->accept(*this);
        for (auto arg : ope.args_) {
            arg->accept(*this);
        }
    }
}

inline void DetectLeftRecursion::visit(Reference &ope) {
    if (ope.name_ == name_) {
        error_s = ope.s_;
    } else if (!refs_.count(ope.name_)) {
        refs_.insert(ope.name_);
        if (ope.rule_) {
            ope.rule_->accept(*this);
            if (done_ == false) { return; }
        }
    }
    done_ = true;
}

inline void HasEmptyElement::visit(Sequence &ope) {
    auto save_is_empty = false;
    const char *save_error_s = nullptr;
    std::string save_error_name;

    auto it = ope.opes_.begin();
    while (it != ope.opes_.end()) {
        (*it)->accept(*this);
        if (!is_empty) {
            ++it;
            while (it != ope.opes_.end()) {
                DetectInfiniteLoop vis(refs_, has_error_cache_);
                (*it)->accept(vis);
                if (vis.has_error) {
                    is_empty = true;
                    error_s = vis.error_s;
                    error_name = vis.error_name;
                }
                ++it;
            }
            return;
        }

        save_is_empty = is_empty;
        save_error_s = error_s;
        save_error_name = error_name;

        is_empty = false;
        error_name.clear();
        ++it;
    }

    is_empty = save_is_empty;
    error_s = save_error_s;
    error_name = save_error_name;
}

inline void HasEmptyElement::visit(Reference &ope) {
    auto it = std::find_if(refs_.begin(), refs_.end(),
                           [&](const std::pair<const char *, std::string> &ref) {
                               return ope.name_ == ref.second;
                           });
    if (it != refs_.end()) { return; }

    if (ope.rule_) {
        refs_.emplace_back(ope.s_, ope.name_);
        ope.rule_->accept(*this);
        refs_.pop_back();
    }
}

inline void DetectInfiniteLoop::visit(Reference &ope) {
    auto it1 = std::find_if(refs_.begin(), refs_.end(),
                           [&](const std::pair<const char *, std::string> &ref) {
                               return ope.name_ == ref.second;
                           });
    if (it1 != refs_.end()) { return; }

    if (ope.rule_) {
        auto it = has_error_cache_.find(ope.name_);
        if (it != has_error_cache_.end()) {
            has_error = it->second;
        } else {
            refs_.emplace_back(ope.s_, ope.name_);
            ope.rule_->accept(*this);
            refs_.pop_back();
            has_error_cache_[ope.name_] = has_error;
        }
    }

    if (ope.is_macro_) {
        for (auto arg : ope.args_) {
            arg->accept(*this);
        }
    }
}

inline void ReferenceChecker::visit(Reference &ope) {
    auto it = std::find(params_.begin(), params_.end(), ope.name_);
    if (it != params_.end()) { return; }

    if (!grammar_.count(ope.name_)) {
        error_s[ope.name_] = ope.s_;
        error_message[ope.name_] = "'" + ope.name_ + "' is not defined.";
    } else {
        if (!referenced.count(ope.name_)) { referenced.insert(ope.name_); }
        const auto &rule = grammar_.at(ope.name_);
        if (rule.is_macro) {
            if (!ope.is_macro_ || ope.args_.size() != rule.params.size()) {
                error_s[ope.name_] = ope.s_;
                error_message[ope.name_] = "incorrect number of arguments.";
            }
        } else if (ope.is_macro_) {
            error_s[ope.name_] = ope.s_;
            error_message[ope.name_] = "'" + ope.name_ + "' is not macro.";
        }
        for (auto arg : ope.args_) {
            arg->accept(*this);
        }
    }
}

inline void LinkReferences::visit(Reference &ope) {
    // Check if the reference is a macro parameter
    auto found_param = false;
    for (size_t i = 0; i < params_.size(); i++) {
        const auto &param = params_[i];
        if (param == ope.name_) {
            ope.iarg_ = i;
            found_param = true;
            break;
        }
    }

    // Check if the reference is a definition rule
    if (!found_param && grammar_.count(ope.name_)) {
        auto &rule = grammar_.at(ope.name_);
        ope.rule_ = &rule;
    }

    for (auto arg : ope.args_) {
        arg->accept(*this);
    }
}

inline void FindReference::visit(Reference &ope) {
    for (size_t i = 0; i < args_.size(); i++) {
        const auto &name = params_[i];
        if (name == ope.name_) {
            found_ope = args_[i];
            return;
        }
    }
    found_ope = ope.shared_from_this();
}

/*-----------------------------------------------------------------------------
 *  PEG parser generator
 *---------------------------------------------------------------------------*/

using Rules = std::unordered_map<std::string, std::shared_ptr<Ope>>;

class ParserGenerator {
public:
    struct ParserContext {
        std::shared_ptr<Grammar> grammar;
        std::string start;
        bool enablePackratParsing = false;
    };

    static ParserContext parse(const char *s, size_t n, const Rules &rules,
                               Log log, std::string_view start) {
        return get_instance().perform_core(s, n, rules, log, std::string(start));
    }

    // For debugging purpose
    static bool parse_test(const char *d, const char *s) {
        Data data;
        std::any dt = &data;

        auto n = strlen(s);
        auto r = get_instance().g[d].parse(s, n, dt);
        return r.ret && r.len == n;
    }

#if defined(__cpp_lib_char8_t)
    static bool parse_test(const char *d, const char8_t *s) {
        return parse_test(d, reinterpret_cast<const char *>(s));
    }
#endif

private:
    static ParserGenerator &get_instance() {
        static ParserGenerator instance;
        return instance;
    }

    ParserGenerator() {
        make_grammar();
        setup_actions();
    }

    struct Instruction {
        std::string type;
        std::any data;
        std::string_view sv;
    };

    struct Data {
        std::shared_ptr<Grammar> grammar;
        std::string start;
        const char *start_pos = nullptr;

        std::vector<std::pair<std::string, const char *>> duplicates_of_definition;

        std::vector<std::pair<std::string, const char *>> duplicates_of_instruction;
        std::map<std::string, std::vector<Instruction>> instructions;

        std::vector<std::pair<std::string, const char *>> undefined_back_references;
        std::vector<std::set<std::string_view>> captures_stack{{}};

        std::set<std::string_view> captures_in_current_definition;
        bool enablePackratParsing = true;

        Data() : grammar(std::make_shared<Grammar>()) {}
    };

    void make_grammar() {
        // Setup PEG syntax parser
        g["Grammar"] <= seq(g["Spacing"], oom(g["Definition"]), g["EndOfFile"]);
        g["Definition"] <=
            cho(seq(g["Ignore"], g["IdentCont"], g["Parameters"], g["LEFTARROW"],
                    g["Expression"], opt(g["Instruction"])),
                seq(g["Ignore"], g["Identifier"], g["LEFTARROW"], g["Expression"],
                    opt(g["Instruction"])));
        g["Expression"] <= seq(g["Sequence"], zom(seq(g["SLASH"], g["Sequence"])));
        g["Sequence"] <= zom(cho(g["CUT"], g["Prefix"]));
        g["Prefix"] <= seq(opt(cho(g["AND"], g["NOT"])), g["SuffixWithLabel"]);
        g["SuffixWithLabel"] <=
            seq(g["Suffix"], opt(seq(g["LABEL"], g["Identifier"])));
        g["Suffix"] <= seq(g["Primary"], opt(g["Loop"]));
        g["Loop"] <= cho(g["QUESTION"], g["STAR"], g["PLUS"], g["Repetition"]);
        g["Primary"] <= cho(seq(g["Ignore"], g["IdentCont"], g["Arguments"],
                                npd(g["LEFTARROW"])),
                            seq(g["Ignore"], g["Identifier"],
                                npd(seq(opt(g["Parameters"]), g["LEFTARROW"]))),
                            seq(g["OPEN"], g["Expression"], g["CLOSE"]),
                            seq(g["BeginTok"], g["Expression"], g["EndTok"]),
                            g["CapScope"],
                            seq(g["BeginCap"], g["Expression"], g["EndCap"]),
                            g["BackRef"], g["DictionaryI"], g["LiteralI"],
                            g["Dictionary"], g["Literal"], g["NegatedClassI"],
                            g["NegatedClass"], g["ClassI"], g["Class"], g["DOT"]);

        g["Identifier"] <= seq(g["IdentCont"], g["Spacing"]);
        g["IdentCont"] <= tok(seq(g["IdentStart"], zom(g["IdentRest"])));

        const static std::vector<std::pair<char32_t, char32_t>> range = {
            {0x0080, 0xFFFF}};
        g["IdentStart"] <= seq(npd(lit(u8(u8"↑"))), npd(lit(u8(u8"⇑"))),
                               cho(cls("a-zA-Z_%"), cls(range)));

        g["IdentRest"] <= cho(g["IdentStart"], cls("0-9"));

        g["Dictionary"] <= seq(g["LiteralD"], oom(seq(g["PIPE"], g["LiteralD"])));

        g["DictionaryI"] <=
            seq(g["LiteralID"], oom(seq(g["PIPE"], g["LiteralID"])));

        auto lit_ope = cho(seq(cls("'"), tok(zom(seq(npd(cls("'")), g["Char"]))),
                               cls("'"), g["Spacing"]),
                           seq(cls("\""), tok(zom(seq(npd(cls("\"")), g["Char"]))),
                               cls("\""), g["Spacing"]));
        g["Literal"] <= lit_ope;
        g["LiteralD"] <= lit_ope;

        auto lit_case_ignore_ope =
            cho(seq(cls("'"), tok(zom(seq(npd(cls("'")), g["Char"]))), lit("'i"),
                    g["Spacing"]),
                seq(cls("\""), tok(zom(seq(npd(cls("\"")), g["Char"]))), lit("\"i"),
                    g["Spacing"]));
        g["LiteralI"] <= lit_case_ignore_ope;
        g["LiteralID"] <= lit_case_ignore_ope;

        // NOTE: The original Brian Ford's paper uses 'zom' instead of 'oom'.
        g["Class"] <= seq(chr('['), npd(chr('^')),
                          tok(oom(seq(npd(chr(']')), g["Range"]))), chr(']'),
                          g["Spacing"]);
        g["ClassI"] <= seq(chr('['), npd(chr('^')),
                           tok(oom(seq(npd(chr(']')), g["Range"]))), lit("]i"),
                           g["Spacing"]);

        g["NegatedClass"] <= seq(lit("[^"),
                                 tok(oom(seq(npd(chr(']')), g["Range"]))), chr(']'),
                                 g["Spacing"]);
        g["NegatedClassI"] <= seq(lit("[^"),
                                  tok(oom(seq(npd(chr(']')), g["Range"]))),
                                  lit("]i"), g["Spacing"]);

        // NOTE: This is different from The original Brian Ford's paper, and this
        // modification allows us to specify `[+-]` as a valid char class.
        g["Range"] <=
            cho(seq(g["Char"], chr('-'), npd(chr(']')), g["Char"]), g["Char"]);

        g["Char"] <=
            cho(seq(chr('\\'), cls("fnrtv'\"[]\\^")),
                seq(chr('\\'), cls("0-3"), cls("0-7"), cls("0-7")),
                seq(chr('\\'), cls("0-7"), opt(cls("0-7"))),
                seq(lit("\\x"), cls("0-9a-fA-F"), opt(cls("0-9a-fA-F"))),
                seq(lit("\\u"),
                    cho(seq(cho(seq(chr('0'), cls("0-9a-fA-F")), lit("10")),
                            rep(cls("0-9a-fA-F"), 4, 4)),
                        rep(cls("0-9a-fA-F"), 4, 5))),
                seq(npd(chr('\\')), dot()));

        g["Repetition"] <=
            seq(g["BeginBracket"], g["RepetitionRange"], g["EndBracket"]);
        g["RepetitionRange"] <= cho(seq(g["Number"], g["COMMA"], g["Number"]),
                                    seq(g["Number"], g["COMMA"]), g["Number"],
                                    seq(g["COMMA"], g["Number"]));
        g["Number"] <= seq(oom(cls("0-9")), g["Spacing"]);

        g["CapScope"] <= seq(g["BeginCapScope"], g["Expression"], g["EndCapScope"]);

        g["LEFTARROW"] <= seq(cho(lit("<-"), lit(u8(u8"←"))), g["Spacing"]);
        ~g["SLASH"] <= seq(chr('/'), g["Spacing"]);
        ~g["PIPE"] <= seq(chr('|'), g["Spacing"]);
        g["AND"] <= seq(chr('&'), g["Spacing"]);
        g["NOT"] <= seq(chr('!'), g["Spacing"]);
        g["QUESTION"] <= seq(chr('?'), g["Spacing"]);
        g["STAR"] <= seq(chr('*'), g["Spacing"]);
        g["PLUS"] <= seq(chr('+'), g["Spacing"]);
        ~g["OPEN"] <= seq(chr('('), g["Spacing"]);
        ~g["CLOSE"] <= seq(chr(')'), g["Spacing"]);
        g["DOT"] <= seq(chr('.'), g["Spacing"]);

        g["CUT"] <= seq(lit(u8(u8"↑")), g["Spacing"]);
        ~g["LABEL"] <= seq(cho(chr('^'), lit(u8(u8"⇑"))), g["Spacing"]);

        ~g["Spacing"] <= zom(cho(g["Space"], g["Comment"]));
        g["Comment"] <=
            seq(chr('#'), zom(seq(npd(g["EndOfLine"]), dot())), g["EndOfLine"]);
        g["Space"] <= cho(chr(' '), chr('\t'), g["EndOfLine"]);
        g["EndOfLine"] <= cho(lit("\r\n"), chr('\n'), chr('\r'));
        g["EndOfFile"] <= npd(dot());

        ~g["BeginTok"] <= seq(chr('<'), g["Spacing"]);
        ~g["EndTok"] <= seq(chr('>'), g["Spacing"]);

        ~g["BeginCapScope"] <= seq(chr('$'), chr('('), g["Spacing"]);
        ~g["EndCapScope"] <= seq(chr(')'), g["Spacing"]);

        g["BeginCap"] <= seq(chr('$'), tok(g["IdentCont"]), chr('<'), g["Spacing"]);
        ~g["EndCap"] <= seq(chr('>'), g["Spacing"]);

        g["BackRef"] <= seq(chr('$'), tok(g["IdentCont"]), g["Spacing"]);

        g["IGNORE"] <= chr('~');

        g["Ignore"] <= opt(g["IGNORE"]);
        g["Parameters"] <= seq(g["OPEN"], g["Identifier"],
                               zom(seq(g["COMMA"], g["Identifier"])), g["CLOSE"]);
        g["Arguments"] <= seq(g["OPEN"], g["Expression"],
                              zom(seq(g["COMMA"], g["Expression"])), g["CLOSE"]);
        ~g["COMMA"] <= seq(chr(','), g["Spacing"]);

        // Instruction grammars
        g["Instruction"] <=
            seq(g["BeginBracket"],
                opt(seq(g["InstructionItem"], zom(seq(g["InstructionItemSeparator"],
                                                      g["InstructionItem"])))),
                g["EndBracket"]);
        g["InstructionItem"] <=
            cho(g["PrecedenceClimbing"], g["ErrorMessage"], g["NoAstOpt"]);
        ~g["InstructionItemSeparator"] <= seq(chr(';'), g["Spacing"]);

        ~g["SpacesZom"] <= zom(g["Space"]);
        ~g["SpacesOom"] <= oom(g["Space"]);
        ~g["BeginBracket"] <= seq(chr('{'), g["Spacing"]);
        ~g["EndBracket"] <= seq(chr('}'), g["Spacing"]);

        // PrecedenceClimbing instruction
        g["PrecedenceClimbing"] <=
            seq(lit("precedence"), g["SpacesOom"], g["PrecedenceInfo"],
                zom(seq(g["SpacesOom"], g["PrecedenceInfo"])), g["SpacesZom"]);
        g["PrecedenceInfo"] <=
            seq(g["PrecedenceAssoc"],
                oom(seq(ign(g["SpacesOom"]), g["PrecedenceOpe"])));
        g["PrecedenceOpe"] <=
            cho(seq(cls("'"),
                    tok(zom(seq(npd(cho(g["Space"], cls("'"))), g["Char"]))),
                    cls("'")),
                seq(cls("\""),
                    tok(zom(seq(npd(cho(g["Space"], cls("\""))), g["Char"]))),
                    cls("\"")),
                tok(oom(seq(npd(cho(g["PrecedenceAssoc"], g["Space"], chr('}'))),
                            dot()))));
        g["PrecedenceAssoc"] <= cls("LR");

        // Error message instruction
        g["ErrorMessage"] <= seq(lit("error_message"), g["SpacesOom"],
                                 g["LiteralD"], g["SpacesZom"]);

        // No Ast node optimization instruction
        g["NoAstOpt"] <= seq(lit("no_ast_opt"), g["SpacesZom"]);

        // Set definition names
        for (auto &x : g) {
            x.second.name = x.first;
        }
    }

    void setup_actions() {
        g["Definition"] = [&](const SemanticValues &vs, std::any &dt) {
            auto &data = *std::any_cast<Data *>(dt);

            auto is_macro = vs.choice() == 0;
            auto ignore = std::any_cast<bool>(vs[0]);
            auto name = std::any_cast<std::string>(vs[1]);

            std::vector<std::string> params;
            std::shared_ptr<Ope> ope;
            auto has_instructions = false;

            if (is_macro) {
                params = std::any_cast<std::vector<std::string>>(vs[2]);
                ope = std::any_cast<std::shared_ptr<Ope>>(vs[4]);
                if (vs.size() == 6) { has_instructions = true; }
            } else {
                ope = std::any_cast<std::shared_ptr<Ope>>(vs[3]);
                if (vs.size() == 5) { has_instructions = true; }
            }

            if (has_instructions) {
                auto index = is_macro ? 5 : 4;
                std::unordered_set<std::string> types;
                for (const auto &instruction :
                     std::any_cast<std::vector<Instruction>>(vs[index])) {
                    const auto &type = instruction.type;
                    if (types.find(type) == types.end()) {
                        data.instructions[name].push_back(instruction);
                        types.insert(instruction.type);
                        if (type == "declare_symbol" || type == "check_symbol") {
                            if (!TokenChecker::is_token(*ope)) { ope = tok(ope); }
                        }
                    } else {
                        data.duplicates_of_instruction.emplace_back(type,
                                                                    instruction.sv.data());
                    }
                }
            }

            auto &grammar = *data.grammar;
            if (!grammar.count(name)) {
                auto &rule = grammar[name];
                rule <= ope;
                rule.name = name;
                rule.s_ = vs.sv().data();
                rule.line_ = line_info(vs.ss, rule.s_);
                rule.ignoreSemanticValue = ignore;
                rule.is_macro = is_macro;
                rule.params = params;

                if (data.start.empty()) {
                    data.start = rule.name;
                    data.start_pos = rule.s_;
                }
            } else {
                data.duplicates_of_definition.emplace_back(name, vs.sv().data());
            }
        };

        g["Definition"].enter = [](const Context & /*c*/, const char * /*s*/,
                                   size_t /*n*/, std::any &dt) {
            auto &data = *std::any_cast<Data *>(dt);
            data.captures_in_current_definition.clear();
        };

        g["Expression"] = [&](const SemanticValues &vs) {
            if (vs.size() == 1) {
                return std::any_cast<std::shared_ptr<Ope>>(vs[0]);
            } else {
                std::vector<std::shared_ptr<Ope>> opes;
                for (auto i = 0u; i < vs.size(); i++) {
                    opes.emplace_back(std::any_cast<std::shared_ptr<Ope>>(vs[i]));
                }
                const std::shared_ptr<Ope> ope =
                    std::make_shared<PrioritizedChoice>(opes);
                return ope;
            }
        };

        g["Sequence"] = [&](const SemanticValues &vs) {
            if (vs.empty()) {
                return npd(lit(""));
            } else if (vs.size() == 1) {
                return std::any_cast<std::shared_ptr<Ope>>(vs[0]);
            } else {
                std::vector<std::shared_ptr<Ope>> opes;
                for (const auto &x : vs) {
                    opes.emplace_back(std::any_cast<std::shared_ptr<Ope>>(x));
                }
                const std::shared_ptr<Ope> ope = std::make_shared<Sequence>(opes);
                return ope;
            }
        };

        g["Prefix"] = [&](const SemanticValues &vs) {
            std::shared_ptr<Ope> ope;
            if (vs.size() == 1) {
                ope = std::any_cast<std::shared_ptr<Ope>>(vs[0]);
            } else {
                assert(vs.size() == 2);
                auto tok = std::any_cast<char>(vs[0]);
                ope = std::any_cast<std::shared_ptr<Ope>>(vs[1]);
                if (tok == '&') {
                    ope = apd(ope);
                } else { // '!'
                    ope = npd(ope);
                }
            }
            return ope;
        };

        g["SuffixWithLabel"] = [&](const SemanticValues &vs, std::any &dt) {
            auto ope = std::any_cast<std::shared_ptr<Ope>>(vs[0]);
            if (vs.size() == 1) {
                return ope;
            } else {
                assert(vs.size() == 2);
                auto &data = *std::any_cast<Data *>(dt);
                const auto &ident = std::any_cast<std::string>(vs[1]);
                auto label = ref(*data.grammar, ident, vs.sv().data(), false, {});
                auto recovery = rec(ref(*data.grammar, RECOVER_DEFINITION_NAME,
                                        vs.sv().data(), true, {label}));
                return cho4label_(ope, recovery);
            }
        };

        struct Loop {
            enum class Type { opt = 0, zom, oom, rep };
            Type type;
            std::pair<size_t, size_t> range;
        };

        g["Suffix"] = [&](const SemanticValues &vs) {
            auto ope = std::any_cast<std::shared_ptr<Ope>>(vs[0]);
            if (vs.size() == 1) {
                return ope;
            } else {
                assert(vs.size() == 2);
                auto loop = std::any_cast<Loop>(vs[1]);
                switch (loop.type) {
                    case Loop::Type::opt: return opt(ope);
                    case Loop::Type::zom: return zom(ope);
                    case Loop::Type::oom: return oom(ope);
                    default: // Regex-like repetition
                        return rep(ope, loop.range.first, loop.range.second);
                }
            }
        };

        g["Loop"] = [&](const SemanticValues &vs) {
            switch (vs.choice()) {
                case 0: // Option
                    return Loop{Loop::Type::opt, std::pair<size_t, size_t>()};
                case 1: // Zero or More
                    return Loop{Loop::Type::zom, std::pair<size_t, size_t>()};
                case 2: // One or More
                    return Loop{Loop::Type::oom, std::pair<size_t, size_t>()};
                default: // Regex-like repetition
                    return Loop{Loop::Type::rep,
                                std::any_cast<std::pair<size_t, size_t>>(vs[0])};
            }
        };

        g["Primary"] = [&](const SemanticValues &vs, std::any &dt) {
            auto &data = *std::any_cast<Data *>(dt);

            switch (vs.choice()) {
                case 0:   // Macro Reference
                case 1: { // Reference
                    auto is_macro = vs.choice() == 0;
                    auto ignore = std::any_cast<bool>(vs[0]);
                    const auto &ident = std::any_cast<std::string>(vs[1]);

                    std::vector<std::shared_ptr<Ope>> args;
                    if (is_macro) {
                        args = std::any_cast<std::vector<std::shared_ptr<Ope>>>(vs[2]);
                    }

                    auto ope = ref(*data.grammar, ident, vs.sv().data(), is_macro, args);
                    if (ident == RECOVER_DEFINITION_NAME) { ope = rec(ope); }

                    if (ignore) {
                        return ign(ope);
                    } else {
                        return ope;
                    }
                }
                case 2: { // (Expression)
                    return std::any_cast<std::shared_ptr<Ope>>(vs[0]);
                }
                case 3: { // TokenBoundary
                    return tok(std::any_cast<std::shared_ptr<Ope>>(vs[0]));
                }
                case 4: { // CaptureScope
                    return csc(std::any_cast<std::shared_ptr<Ope>>(vs[0]));
                }
                case 5: { // Capture
                    const auto &name = std::any_cast<std::string_view>(vs[0]);
                    auto ope = std::any_cast<std::shared_ptr<Ope>>(vs[1]);

                    data.captures_stack.back().insert(name);
                    data.captures_in_current_definition.insert(name);

                    return cap(ope, [name](const char *a_s, size_t a_n, Context &c) {
                        auto &cs = c.capture_scope_stack[c.capture_scope_stack_size - 1];
                        cs[name] = std::string(a_s, a_n);
                    });
                }
                default: {
                    return std::any_cast<std::shared_ptr<Ope>>(vs[0]);
                }
            }
        };

        g["IdentCont"] = [](const SemanticValues &vs) {
            return std::string(vs.sv().data(), vs.sv().length());
        };

        g["Dictionary"] = [](const SemanticValues &vs) {
            auto items = vs.transform<std::string>();
            return dic(items, false);
        };
        g["DictionaryI"] = [](const SemanticValues &vs) {
            auto items = vs.transform<std::string>();
            return dic(items, true);
        };

        g["Literal"] = [](const SemanticValues &vs) {
            const auto &tok = vs.tokens.front();
            return lit(resolve_escape_sequence(tok.data(), tok.size()));
        };
        g["LiteralI"] = [](const SemanticValues &vs) {
            const auto &tok = vs.tokens.front();
            return liti(resolve_escape_sequence(tok.data(), tok.size()));
        };
        g["LiteralD"] = [](const SemanticValues &vs) {
            auto &tok = vs.tokens.front();
            return resolve_escape_sequence(tok.data(), tok.size());
        };
        g["LiteralID"] = [](const SemanticValues &vs) {
            auto &tok = vs.tokens.front();
            return resolve_escape_sequence(tok.data(), tok.size());
        };

        g["Class"] = [](const SemanticValues &vs) {
            auto ranges = vs.transform<std::pair<char32_t, char32_t>>();
            return cls(ranges);
        };
        g["ClassI"] = [](const SemanticValues &vs) {
            auto ranges = vs.transform<std::pair<char32_t, char32_t>>();
            return cls(ranges, true);
        };
        g["NegatedClass"] = [](const SemanticValues &vs) {
            auto ranges = vs.transform<std::pair<char32_t, char32_t>>();
            return ncls(ranges);
        };
        g["NegatedClassI"] = [](const SemanticValues &vs) {
            auto ranges = vs.transform<std::pair<char32_t, char32_t>>();
            return ncls(ranges, true);
        };
        g["Range"] = [](const SemanticValues &vs) {
            switch (vs.choice()) {
                case 0: {
                    auto s1 = std::any_cast<std::string>(vs[0]);
                    auto s2 = std::any_cast<std::string>(vs[1]);
                    auto cp1 = decode_codepoint(s1.data(), s1.length());
                    auto cp2 = decode_codepoint(s2.data(), s2.length());
                    return std::pair(cp1, cp2);
                }
                case 1: {
                    auto s = std::any_cast<std::string>(vs[0]);
                    auto cp = decode_codepoint(s.data(), s.length());
                    return std::pair(cp, cp);
                }
            }
            return std::pair<char32_t, char32_t>(0, 0);
        };
        g["Char"] = [](const SemanticValues &vs) {
            return resolve_escape_sequence(vs.sv().data(), vs.sv().length());
        };

        g["RepetitionRange"] = [&](const SemanticValues &vs) {
            switch (vs.choice()) {
                case 0: { // Number COMMA Number
                    auto min = std::any_cast<size_t>(vs[0]);
                    auto max = std::any_cast<size_t>(vs[1]);
                    return std::pair(min, max);
                }
                case 1: // Number COMMA
                    return std::pair(std::any_cast<size_t>(vs[0]),
                                     std::numeric_limits<size_t>::max());
                case 2: { // Number
                    auto n = std::any_cast<size_t>(vs[0]);
                    return std::pair(n, n);
                }
                default: // COMMA Number
                    return std::pair(std::numeric_limits<size_t>::min(),
                                     std::any_cast<size_t>(vs[0]));
            }
        };
        g["Number"] = [&](const SemanticValues &vs) {
            return vs.token_to_number<size_t>();
        };

        g["CapScope"].enter = [](const Context & /*c*/, const char * /*s*/,
                                 size_t /*n*/, std::any &dt) {
            auto &data = *std::any_cast<Data *>(dt);
            data.captures_stack.emplace_back();
        };
        g["CapScope"].leave = [](const Context & /*c*/, const char * /*s*/,
                                 size_t /*n*/, size_t /*matchlen*/,
                                 std::any & /*value*/, std::any &dt) {
            auto &data = *std::any_cast<Data *>(dt);
            data.captures_stack.pop_back();
        };

        g["AND"] = [](const SemanticValues &vs) { return *vs.sv().data(); };
        g["NOT"] = [](const SemanticValues &vs) { return *vs.sv().data(); };
        g["QUESTION"] = [](const SemanticValues &vs) { return *vs.sv().data(); };
        g["STAR"] = [](const SemanticValues &vs) { return *vs.sv().data(); };
        g["PLUS"] = [](const SemanticValues &vs) { return *vs.sv().data(); };

        g["DOT"] = [](const SemanticValues & /*vs*/) { return dot(); };

        g["CUT"] = [](const SemanticValues & /*vs*/) { return cut(); };

        g["BeginCap"] = [](const SemanticValues &vs) { return vs.token(); };

        g["BackRef"] = [&](const SemanticValues &vs, std::any &dt) {
            auto &data = *std::any_cast<Data *>(dt);

            // Undefined back reference check
            {
                auto found = false;
                auto it = data.captures_stack.rbegin();
                while (it != data.captures_stack.rend()) {
                    if (it->find(vs.token()) != it->end()) {
                        found = true;
                        break;
                    }
                    ++it;
                }
                if (!found) {
                    auto ptr = vs.token().data() - 1; // include '$' symbol
                    data.undefined_back_references.emplace_back(vs.token(), ptr);
                }
            }

            // NOTE: Disable packrat parsing if a back reference is not defined in
            // captures in the current definition rule.
            if (data.captures_in_current_definition.find(vs.token()) ==
                data.captures_in_current_definition.end()) {
                data.enablePackratParsing = false;
            }

            return bkr(vs.token_to_string());
        };

        g["Ignore"] = [](const SemanticValues &vs) { return vs.size() > 0; };

        g["Parameters"] = [](const SemanticValues &vs) {
            return vs.transform<std::string>();
        };

        g["Arguments"] = [](const SemanticValues &vs) {
            return vs.transform<std::shared_ptr<Ope>>();
        };

        g["PrecedenceClimbing"] = [](const SemanticValues &vs) {
            PrecedenceClimbing::BinOpeInfo binOpeInfo;
            size_t level = 1;
            for (auto v : vs) {
                auto tokens = std::any_cast<std::vector<std::string_view>>(v);
                auto assoc = tokens[0][0];
                for (size_t i = 1; i < tokens.size(); i++) {
                    binOpeInfo[tokens[i]] = std::pair(level, assoc);
                }
                level++;
            }
            Instruction instruction;
            instruction.type = "precedence";
            instruction.data = binOpeInfo;
            instruction.sv = vs.sv();
            return instruction;
        };
        g["PrecedenceInfo"] = [](const SemanticValues &vs) {
            return vs.transform<std::string_view>();
        };
        g["PrecedenceOpe"] = [](const SemanticValues &vs) { return vs.token(); };
        g["PrecedenceAssoc"] = [](const SemanticValues &vs) { return vs.token(); };

        g["ErrorMessage"] = [](const SemanticValues &vs) {
            Instruction instruction;
            instruction.type = "error_message";
            instruction.data = std::any_cast<std::string>(vs[0]);
            instruction.sv = vs.sv();
            return instruction;
        };

        g["NoAstOpt"] = [](const SemanticValues &vs) {
            Instruction instruction;
            instruction.type = "no_ast_opt";
            instruction.sv = vs.sv();
            return instruction;
        };

        g["Instruction"] = [](const SemanticValues &vs) {
            return vs.transform<Instruction>();
        };
    }

    bool apply_precedence_instruction(Definition &rule,
                                      const PrecedenceClimbing::BinOpeInfo &info,
                                      const char *s, Log log) {
        try {
            auto &seq = dynamic_cast<Sequence &>(*rule.get_core_operator());
            auto atom = seq.opes_[0];
            auto &rep = dynamic_cast<Repetition &>(*seq.opes_[1]);
            auto &seq1 = dynamic_cast<Sequence &>(*rep.ope_);
            auto binop = seq1.opes_[0];
            auto atom1 = seq1.opes_[1];

            auto atom_name = dynamic_cast<Reference &>(*atom).name_;
            auto binop_name = dynamic_cast<Reference &>(*binop).name_;
            auto atom1_name = dynamic_cast<Reference &>(*atom1).name_;

            if (!rep.is_zom() || atom_name != atom1_name || atom_name == binop_name) {
                if (log) {
                    auto line = line_info(s, rule.s_);
                    log(line.first, line.second,
                        "'precedence' instruction cannot be applied to '" + rule.name +
                            "'.",
                        "");
                }
                return false;
            }

            rule.holder_->ope_ = pre(atom, binop, info, rule);
            rule.disable_action = true;
        } catch (...) {
            if (log) {
                auto line = line_info(s, rule.s_);
                log(line.first, line.second,
                    "'precedence' instruction cannot be applied to '" + rule.name +
                        "'.",
                    "");
            }
            return false;
        }
        return true;
    }

    ParserContext perform_core(const char *s, size_t n, const Rules &rules,
                               Log log, std::string requested_start) {
        Data data;
        auto &grammar = *data.grammar;

        // Built-in macros
        {
            // `%recover`
            {
                auto &rule = grammar[RECOVER_DEFINITION_NAME];
                rule <= ref(grammar, "x", "", false, {});
                rule.name = RECOVER_DEFINITION_NAME;
                rule.s_ = "[native]";
                rule.ignoreSemanticValue = true;
                rule.is_macro = true;
                rule.params = {"x"};
            }
        }

        std::any dt = &data;
        auto r = g["Grammar"].parse(s, n, dt, nullptr, log);

        if (!r.ret) {
            if (log) {
                if (r.error_info.message_pos) {
                    auto line = line_info(s, r.error_info.message_pos);
                    log(line.first, line.second, r.error_info.message,
                        r.error_info.label);
                } else {
                    auto line = line_info(s, r.error_info.error_pos);
                    log(line.first, line.second, "syntax error", r.error_info.label);
                }
            }
            return {};
        }

        // User provided rules
        for (auto [user_name, user_rule] : rules) {
            auto name = user_name;
            auto ignore = false;
            if (!name.empty() && name[0] == '~') {
                ignore = true;
                name.erase(0, 1);
            }
            if (!name.empty()) {
                auto &rule = grammar[name];
                rule <= user_rule;
                rule.name = name;
                rule.ignoreSemanticValue = ignore;
            }
        }

        // Check duplicated definitions
        auto ret = true;

        if (!data.duplicates_of_definition.empty()) {
            for (const auto &[name, ptr] : data.duplicates_of_definition) {
                if (log) {
                    auto line = line_info(s, ptr);
                    log(line.first, line.second,
                        "The definition '" + name + "' is already defined.", "");
                }
            }
            ret = false;
        }

        // Check duplicated instructions
        if (!data.duplicates_of_instruction.empty()) {
            for (const auto &[type, ptr] : data.duplicates_of_instruction) {
                if (log) {
                    auto line = line_info(s, ptr);
                    log(line.first, line.second,
                        "The instruction '" + type + "' is already defined.", "");
                }
            }
            ret = false;
        }

        // Check undefined back references
        if (!data.undefined_back_references.empty()) {
            for (const auto &[name, ptr] : data.undefined_back_references) {
                if (log) {
                    auto line = line_info(s, ptr);
                    log(line.first, line.second,
                        "The back reference '" + name + "' is undefined.", "");
                }
            }
            ret = false;
        }

        // Set root definition
        auto start = data.start;

        if (!requested_start.empty()) {
            if (grammar.count(requested_start)) {
                start = requested_start;
            } else {
                if (log) {
                    auto line = line_info(s, s);
                    log(line.first, line.second,
                        "The specified start rule '" + requested_start +
                            "' is undefined.",
                        "");
                }
                ret = false;
            }
        }

        if (!ret) { return {}; }

        auto &start_rule = grammar[start];

        // Check if the start rule has ignore operator
        {
            if (start_rule.ignoreSemanticValue) {
                if (log) {
                    auto line = line_info(s, start_rule.s_);
                    log(line.first, line.second,
                        "Ignore operator cannot be applied to '" + start_rule.name + "'.",
                        "");
                }
                ret = false;
            }
        }

        if (!ret) { return {}; }

        // Check missing definitions
        auto referenced = std::unordered_set<std::string>{
            WHITESPACE_DEFINITION_NAME,
            WORD_DEFINITION_NAME,
            RECOVER_DEFINITION_NAME,
            start_rule.name,
        };

        for (auto &[_, rule] : grammar) {
            ReferenceChecker vis(grammar, rule.params);
            rule.accept(vis);
            referenced.insert(vis.referenced.begin(), vis.referenced.end());
            for (const auto &[name, ptr] : vis.error_s) {
                if (log) {
                    auto line = line_info(s, ptr);
                    log(line.first, line.second, vis.error_message[name], "");
                }
                ret = false;
            }
        }

        for (auto &[name, rule] : grammar) {
            if (!referenced.count(name)) {
                if (log) {
                    auto line = line_info(s, rule.s_);
                    auto msg = "'" + name + "' is not referenced.";
                    log(line.first, line.second, msg, "");
                }
            }
        }

        if (!ret) { return {}; }

        // Link references
        for (auto &x : grammar) {
            auto &rule = x.second;
            LinkReferences vis(grammar, rule.params);
            rule.accept(vis);
        }

        // Check left recursion
        ret = true;

        for (auto &[name, rule] : grammar) {
            DetectLeftRecursion vis(name);
            rule.accept(vis);
            if (vis.error_s) {
                if (log) {
                    auto line = line_info(s, vis.error_s);
                    log(line.first, line.second, "'" + name + "' is left recursive.", "");
                }
                ret = false;
            }
        }

        if (!ret) { return {}; }

        // Check infinite loop
        if (detect_infiniteLoop(data, start_rule, log, s)) { return {}; }

        // Automatic whitespace skipping
        if (grammar.count(WHITESPACE_DEFINITION_NAME)) {
            for (auto &x : grammar) {
                auto &rule = x.second;
                auto ope = rule.get_core_operator();
                if (IsLiteralToken::check(*ope)) { rule <= tok(ope); }
            }

            auto &rule = grammar[WHITESPACE_DEFINITION_NAME];
            start_rule.whitespaceOpe = wsp(rule.get_core_operator());

            if (detect_infiniteLoop(data, rule, log, s)) { return {}; }
        }

        // Word expression
        if (grammar.count(WORD_DEFINITION_NAME)) {
            auto &rule = grammar[WORD_DEFINITION_NAME];
            start_rule.wordOpe = rule.get_core_operator();

            if (detect_infiniteLoop(data, rule, log, s)) { return {}; }
        }

        // Apply instructions
        for (const auto &[name, instructions] : data.instructions) {
            auto &rule = grammar[name];

            for (const auto &instruction : instructions) {
                if (instruction.type == "precedence") {
                    const auto &info =
                        std::any_cast<PrecedenceClimbing::BinOpeInfo>(instruction.data);

                    if (!apply_precedence_instruction(rule, info, s, log)) { return {}; }
                } else if (instruction.type == "error_message") {
                    rule.error_message = std::any_cast<std::string>(instruction.data);
                } else if (instruction.type == "no_ast_opt") {
                    rule.no_ast_opt = true;
                }
            }
        }

        return {data.grammar, start, data.enablePackratParsing};
    }

    bool detect_infiniteLoop(const Data &data, Definition &rule, const Log &log,
                             const char *s) const {
        std::vector<std::pair<const char *, std::string>> refs;
        std::unordered_map<std::string, bool> has_error_cache;
        DetectInfiniteLoop vis(data.start_pos, rule.name, refs, has_error_cache);
        rule.accept(vis);
        if (vis.has_error) {
            if (log) {
                auto line = line_info(s, vis.error_s);
                log(line.first, line.second,
                    "infinite loop is detected in '" + vis.error_name + "'.", "");
            }
            return true;
        }
        return false;
    }

    Grammar g;
};

/*-----------------------------------------------------------------------------
 *  AST
 *---------------------------------------------------------------------------*/

template <typename Annotation> struct AstBase : public Annotation {
    AstBase(const char *path, size_t line, size_t column, const char *name,
            const std::vector<std::shared_ptr<AstBase>> &nodes,
            size_t position = 0, size_t length = 0, size_t choice_count = 0,
            size_t choice = 0)
        : path(path ? path : ""), line(line), column(column), name(name),
          position(position), length(length), choice_count(choice_count),
          choice(choice), original_name(name),
          original_choice_count(choice_count), original_choice(choice),
          tag(str2tag(name)), original_tag(tag), is_token(false), nodes(nodes) {}

    AstBase(const char *path, size_t line, size_t column, const char *name,
            const std::string_view &token, size_t position = 0, size_t length = 0,
            size_t choice_count = 0, size_t choice = 0)
        : path(path ? path : ""), line(line), column(column), name(name),
          position(position), length(length), choice_count(choice_count),
          choice(choice), original_name(name),
          original_choice_count(choice_count), original_choice(choice),
          tag(str2tag(name)), original_tag(tag), is_token(true), token(token) {}

    AstBase(const AstBase &ast, const char *original_name, size_t position = 0,
            size_t length = 0, size_t original_choice_count = 0,
            size_t original_choice = 0)
        : path(ast.path), line(ast.line), column(ast.column), name(ast.name),
          position(position), length(length), choice_count(ast.choice_count),
          choice(ast.choice), original_name(original_name),
          original_choice_count(original_choice_count),
          original_choice(original_choice), tag(ast.tag),
          original_tag(str2tag(original_name)), is_token(ast.is_token),
          token(ast.token), nodes(ast.nodes), parent(ast.parent) {}

    const std::string path;
    const size_t line = 1;
    const size_t column = 1;

    const std::string name;
    size_t position;
    size_t length;
    const size_t choice_count;
    const size_t choice;
    const std::string original_name;
    const size_t original_choice_count;
    const size_t original_choice;
    const unsigned int tag;
    const unsigned int original_tag;

    const bool is_token;
    const std::string_view token;

    std::vector<std::shared_ptr<AstBase<Annotation>>> nodes;
    std::weak_ptr<AstBase<Annotation>> parent;

    std::string token_to_string() const {
        assert(is_token);
        return std::string(token);
    }

    template <typename T> T token_to_number() const {
        return token_to_number_<T>(token);
    }
};

template <typename T>
void ast_to_s_core(const std::shared_ptr<T> &ptr, std::string &s, int level,
                   std::function<std::string(const T &ast, int level)> fn) {
    const auto &ast = *ptr;
    for (auto i = 0; i < level; i++) {
        s += "  ";
    }
    auto name = ast.original_name;
    if (ast.original_choice_count > 0) {
        name += "/" + std::to_string(ast.original_choice);
    }
    if (ast.name != ast.original_name) { name += "[" + ast.name + "]"; }
    if (ast.is_token) {
        s += "- " + name + " (";
        s += ast.token;
        s += ")\n";
    } else {
        s += "+ " + name + "\n";
    }
    if (fn) { s += fn(ast, level + 1); }
    for (auto node : ast.nodes) {
        ast_to_s_core(node, s, level + 1, fn);
    }
}

template <typename T>
std::string
ast_to_s(const std::shared_ptr<T> &ptr,
         std::function<std::string(const T &ast, int level)> fn = nullptr) {
    std::string s;
    ast_to_s_core(ptr, s, 0, fn);
    return s;
}

struct AstOptimizer {
    AstOptimizer(bool mode, const std::vector<std::string> &rules = {})
        : mode_(mode), rules_(rules) {}

    template <typename T>
    std::shared_ptr<T> optimize(std::shared_ptr<T> original,
                                std::shared_ptr<T> parent = nullptr) {
        auto found =
            std::find(rules_.begin(), rules_.end(), original->name) != rules_.end();
        auto opt = mode_ ? !found : found;

        if (opt && original->nodes.size() == 1) {
            auto child = optimize(original->nodes[0], parent);
            auto ast = std::make_shared<T>(*child, original->name.data(),
                                           original->choice_count, original->position,
                                           original->length, original->choice);
            for (auto node : ast->nodes) {
                node->parent = ast;
            }
            return ast;
        }

        auto ast = std::make_shared<T>(*original);
        ast->parent = parent;
        ast->nodes.clear();
        for (auto node : original->nodes) {
            auto child = optimize(node, ast);
            ast->nodes.push_back(child);
        }
        return ast;
    }

private:
    const bool mode_;
    const std::vector<std::string> rules_;
};

struct EmptyType {};
using Ast = AstBase<EmptyType>;

template <typename T = Ast> void add_ast_action(Definition &rule) {
    rule.action = [&](const SemanticValues &vs) {
        auto line = vs.line_info();

        if (rule.is_token()) {
            return std::make_shared<T>(
                vs.path, line.first, line.second, rule.name.data(), vs.token(),
                std::distance(vs.ss, vs.sv().data()), vs.sv().length(),
                vs.choice_count(), vs.choice());
        }

        auto ast =
            std::make_shared<T>(vs.path, line.first, line.second, rule.name.data(),
                                vs.transform<std::shared_ptr<T>>(),
                                std::distance(vs.ss, vs.sv().data()),
                                vs.sv().length(), vs.choice_count(), vs.choice());

        for (auto node : ast->nodes) {
            node->parent = ast;
        }
        return ast;
    };
}

#define PEG_EXPAND(...) __VA_ARGS__
#define PEG_CONCAT(a, b) a##b
#define PEG_CONCAT2(a, b) PEG_CONCAT(a, b)

#define PEG_PICK(                                                              \
    a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, \
    a17, a18, a19, a20, a21, a22, a23, a24, a25, a26, a27, a28, a29, a30, a31, \
    a32, a33, a34, a35, a36, a37, a38, a39, a40, a41, a42, a43, a44, a45, a46, \
    a47, a48, a49, a50, a51, a52, a53, a54, a55, a56, a57, a58, a59, a60, a61, \
    a62, a63, a64, a65, a66, a67, a68, a69, a70, a71, a72, a73, a74, a75, a76, \
    a77, a78, a79, a80, a81, a82, a83, a84, a85, a86, a87, a88, a89, a90, a91, \
    a92, a93, a94, a95, a96, a97, a98, a99, a100, ...)                         \
  a100

#define PEG_COUNT(...)                                                         \
  PEG_EXPAND(PEG_PICK(                                                         \
      __VA_ARGS__, 100, 99, 98, 97, 96, 95, 94, 93, 92, 91, 90, 89, 88, 87,    \
      86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69,  \
      68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51,  \
      50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33,  \
      32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15,  \
      14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0))

#define PEG_DEF_1(r)                                                           \
  peg::Definition r;                                                           \
  r.name = #r;                                                                 \
  peg::add_ast_action(r);

#define PEG_DEF_2(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_1(__VA_ARGS__))
#define PEG_DEF_3(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_2(__VA_ARGS__))
#define PEG_DEF_4(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_3(__VA_ARGS__))
#define PEG_DEF_5(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_4(__VA_ARGS__))
#define PEG_DEF_6(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_5(__VA_ARGS__))
#define PEG_DEF_7(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_6(__VA_ARGS__))
#define PEG_DEF_8(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_7(__VA_ARGS__))
#define PEG_DEF_9(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_8(__VA_ARGS__))
#define PEG_DEF_10(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_9(__VA_ARGS__))
#define PEG_DEF_11(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_10(__VA_ARGS__))
#define PEG_DEF_12(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_11(__VA_ARGS__))
#define PEG_DEF_13(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_12(__VA_ARGS__))
#define PEG_DEF_14(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_13(__VA_ARGS__))
#define PEG_DEF_15(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_14(__VA_ARGS__))
#define PEG_DEF_16(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_15(__VA_ARGS__))
#define PEG_DEF_17(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_16(__VA_ARGS__))
#define PEG_DEF_18(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_17(__VA_ARGS__))
#define PEG_DEF_19(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_18(__VA_ARGS__))
#define PEG_DEF_20(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_19(__VA_ARGS__))
#define PEG_DEF_21(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_20(__VA_ARGS__))
#define PEG_DEF_22(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_21(__VA_ARGS__))
#define PEG_DEF_23(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_22(__VA_ARGS__))
#define PEG_DEF_24(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_23(__VA_ARGS__))
#define PEG_DEF_25(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_24(__VA_ARGS__))
#define PEG_DEF_26(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_25(__VA_ARGS__))
#define PEG_DEF_27(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_26(__VA_ARGS__))
#define PEG_DEF_28(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_27(__VA_ARGS__))
#define PEG_DEF_29(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_28(__VA_ARGS__))
#define PEG_DEF_30(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_29(__VA_ARGS__))
#define PEG_DEF_31(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_30(__VA_ARGS__))
#define PEG_DEF_32(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_31(__VA_ARGS__))
#define PEG_DEF_33(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_32(__VA_ARGS__))
#define PEG_DEF_34(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_33(__VA_ARGS__))
#define PEG_DEF_35(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_34(__VA_ARGS__))
#define PEG_DEF_36(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_35(__VA_ARGS__))
#define PEG_DEF_37(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_36(__VA_ARGS__))
#define PEG_DEF_38(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_37(__VA_ARGS__))
#define PEG_DEF_39(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_38(__VA_ARGS__))
#define PEG_DEF_40(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_39(__VA_ARGS__))
#define PEG_DEF_41(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_40(__VA_ARGS__))
#define PEG_DEF_42(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_41(__VA_ARGS__))
#define PEG_DEF_43(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_42(__VA_ARGS__))
#define PEG_DEF_44(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_43(__VA_ARGS__))
#define PEG_DEF_45(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_44(__VA_ARGS__))
#define PEG_DEF_46(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_45(__VA_ARGS__))
#define PEG_DEF_47(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_46(__VA_ARGS__))
#define PEG_DEF_48(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_47(__VA_ARGS__))
#define PEG_DEF_49(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_48(__VA_ARGS__))
#define PEG_DEF_50(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_49(__VA_ARGS__))
#define PEG_DEF_51(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_50(__VA_ARGS__))
#define PEG_DEF_52(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_51(__VA_ARGS__))
#define PEG_DEF_53(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_52(__VA_ARGS__))
#define PEG_DEF_54(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_53(__VA_ARGS__))
#define PEG_DEF_55(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_54(__VA_ARGS__))
#define PEG_DEF_56(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_55(__VA_ARGS__))
#define PEG_DEF_57(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_56(__VA_ARGS__))
#define PEG_DEF_58(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_57(__VA_ARGS__))
#define PEG_DEF_59(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_58(__VA_ARGS__))
#define PEG_DEF_60(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_59(__VA_ARGS__))
#define PEG_DEF_61(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_60(__VA_ARGS__))
#define PEG_DEF_62(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_61(__VA_ARGS__))
#define PEG_DEF_63(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_62(__VA_ARGS__))
#define PEG_DEF_64(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_63(__VA_ARGS__))
#define PEG_DEF_65(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_64(__VA_ARGS__))
#define PEG_DEF_66(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_65(__VA_ARGS__))
#define PEG_DEF_67(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_66(__VA_ARGS__))
#define PEG_DEF_68(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_67(__VA_ARGS__))
#define PEG_DEF_69(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_68(__VA_ARGS__))
#define PEG_DEF_70(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_69(__VA_ARGS__))
#define PEG_DEF_71(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_70(__VA_ARGS__))
#define PEG_DEF_72(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_71(__VA_ARGS__))
#define PEG_DEF_73(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_72(__VA_ARGS__))
#define PEG_DEF_74(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_73(__VA_ARGS__))
#define PEG_DEF_75(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_74(__VA_ARGS__))
#define PEG_DEF_76(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_75(__VA_ARGS__))
#define PEG_DEF_77(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_76(__VA_ARGS__))
#define PEG_DEF_78(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_77(__VA_ARGS__))
#define PEG_DEF_79(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_78(__VA_ARGS__))
#define PEG_DEF_80(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_79(__VA_ARGS__))
#define PEG_DEF_81(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_80(__VA_ARGS__))
#define PEG_DEF_82(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_81(__VA_ARGS__))
#define PEG_DEF_83(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_82(__VA_ARGS__))
#define PEG_DEF_84(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_83(__VA_ARGS__))
#define PEG_DEF_85(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_84(__VA_ARGS__))
#define PEG_DEF_86(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_85(__VA_ARGS__))
#define PEG_DEF_87(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_86(__VA_ARGS__))
#define PEG_DEF_88(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_87(__VA_ARGS__))
#define PEG_DEF_89(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_88(__VA_ARGS__))
#define PEG_DEF_90(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_89(__VA_ARGS__))
#define PEG_DEF_91(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_90(__VA_ARGS__))
#define PEG_DEF_92(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_91(__VA_ARGS__))
#define PEG_DEF_93(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_92(__VA_ARGS__))
#define PEG_DEF_94(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_93(__VA_ARGS__))
#define PEG_DEF_95(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_94(__VA_ARGS__))
#define PEG_DEF_96(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_95(__VA_ARGS__))
#define PEG_DEF_97(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_96(__VA_ARGS__))
#define PEG_DEF_98(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_97(__VA_ARGS__))
#define PEG_DEF_99(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_98(__VA_ARGS__))
#define PEG_DEF_100(r1, ...) PEG_EXPAND(PEG_DEF_1(r1) PEG_DEF_99(__VA_ARGS__))

#define AST_DEFINITIONS(...)                                                   \
  PEG_EXPAND(PEG_CONCAT2(PEG_DEF_, PEG_COUNT(__VA_ARGS__))(__VA_ARGS__))

/*-----------------------------------------------------------------------------
 *  parser
 *---------------------------------------------------------------------------*/

class parser {
public:
    parser() = default;

    parser(const char *s, size_t n, const Rules &rules,
           std::string_view start = {}) {
        load_grammar(s, n, rules, start);
    }

    parser(const char *s, size_t n, std::string_view start = {})
        : parser(s, n, Rules(), start) {}

    parser(std::string_view sv, const Rules &rules, std::string_view start = {})
        : parser(sv.data(), sv.size(), rules, start) {}

    parser(std::string_view sv, std::string_view start = {})
        : parser(sv.data(), sv.size(), Rules(), start) {}

#if defined(__cpp_lib_char8_t)
    parser(std::u8string_view sv, const Rules &rules, std::string_view start = {})
        : parser(reinterpret_cast<const char *>(sv.data()), sv.size(), rules,
                 start) {}

    parser(std::u8string_view sv, std::string_view start = {})
        : parser(reinterpret_cast<const char *>(sv.data()), sv.size(), Rules(),
                 start) {}
#endif

    operator bool() { return grammar_ != nullptr; }

    bool load_grammar(const char *s, size_t n, const Rules &rules,
                      std::string_view start = {}) {
        auto cxt = ParserGenerator::parse(s, n, rules, log_, start);
        grammar_ = cxt.grammar;
        start_ = cxt.start;
        enablePackratParsing_ = cxt.enablePackratParsing;
        return grammar_ != nullptr;
    }

    bool load_grammar(const char *s, size_t n, std::string_view start = {}) {
        return load_grammar(s, n, Rules(), start);
    }

    bool load_grammar(std::string_view sv, const Rules &rules,
                      std::string_view start = {}) {
        return load_grammar(sv.data(), sv.size(), rules, start);
    }

    bool load_grammar(std::string_view sv, std::string_view start = {}) {
        return load_grammar(sv.data(), sv.size(), start);
    }

    bool parse_n(const char *s, size_t n, const char *path = nullptr) const {
        if (grammar_ != nullptr) {
            const auto &rule = (*grammar_)[start_];
            auto result = rule.parse(s, n, path, log_);
            return post_process(s, n, result);
        }
        return false;
    }

    bool parse_n(const char *s, size_t n, std::any &dt,
                 const char *path = nullptr) const {
        if (grammar_ != nullptr) {
            const auto &rule = (*grammar_)[start_];
            auto result = rule.parse(s, n, dt, path, log_);
            return post_process(s, n, result);
        }
        return false;
    }

    template <typename T>
    bool parse_n(const char *s, size_t n, T &val,
                 const char *path = nullptr) const {
        if (grammar_ != nullptr) {
            const auto &rule = (*grammar_)[start_];
            auto result = rule.parse_and_get_value(s, n, val, path, log_);
            return post_process(s, n, result);
        }
        return false;
    }

    template <typename T>
    bool parse_n(const char *s, size_t n, std::any &dt, T &val,
                 const char *path = nullptr) const {
        if (grammar_ != nullptr) {
            const auto &rule = (*grammar_)[start_];
            auto result = rule.parse_and_get_value(s, n, dt, val, path, log_);
            return post_process(s, n, result);
        }
        return false;
    }

    bool parse(std::string_view sv, const char *path = nullptr) const {
        return parse_n(sv.data(), sv.size(), path);
    }

    bool parse(std::string_view sv, std::any &dt,
               const char *path = nullptr) const {
        return parse_n(sv.data(), sv.size(), dt, path);
    }

    template <typename T>
    bool parse(std::string_view sv, T &val, const char *path = nullptr) const {
        return parse_n(sv.data(), sv.size(), val, path);
    }

    template <typename T>
    bool parse(std::string_view sv, std::any &dt, T &val,
               const char *path = nullptr) const {
        return parse_n(sv.data(), sv.size(), dt, val, path);
    }

#if defined(__cpp_lib_char8_t)
    bool parse(std::u8string_view sv, const char *path = nullptr) const {
        return parse_n(reinterpret_cast<const char *>(sv.data()), sv.size(), path);
    }

    bool parse(std::u8string_view sv, std::any &dt,
               const char *path = nullptr) const {
        return parse_n(reinterpret_cast<const char *>(sv.data()), sv.size(), dt,
                       path);
    }

    template <typename T>
    bool parse(std::u8string_view sv, T &val, const char *path = nullptr) const {
        return parse_n(reinterpret_cast<const char *>(sv.data()), sv.size(), val,
                       path);
    }

    template <typename T>
    bool parse(std::u8string_view sv, std::any &dt, T &val,
               const char *path = nullptr) const {
        return parse_n(reinterpret_cast<const char *>(sv.data()), sv.size(), dt,
                       val, path);
    }
#endif

    Definition &operator[](const char *s) { return (*grammar_)[s]; }

    const Definition &operator[](const char *s) const { return (*grammar_)[s]; }

    const Grammar &get_grammar() const { return *grammar_; }

    void disable_eoi_check() {
        if (grammar_ != nullptr) {
            auto &rule = (*grammar_)[start_];
            rule.eoi_check = false;
        }
    }

    void enable_packrat_parsing() {
        if (grammar_ != nullptr) {
            auto &rule = (*grammar_)[start_];
            rule.enablePackratParsing = enablePackratParsing_;
        }
    }

    void enable_trace(TracerEnter tracer_enter, TracerLeave tracer_leave) {
        if (grammar_ != nullptr) {
            auto &rule = (*grammar_)[start_];
            rule.tracer_enter = tracer_enter;
            rule.tracer_leave = tracer_leave;
        }
    }

    void enable_trace(TracerEnter tracer_enter, TracerLeave tracer_leave,
                      TracerStartOrEnd tracer_start,
                      TracerStartOrEnd tracer_end) {
        if (grammar_ != nullptr) {
            auto &rule = (*grammar_)[start_];
            rule.tracer_enter = tracer_enter;
            rule.tracer_leave = tracer_leave;
            rule.tracer_start = tracer_start;
            rule.tracer_end = tracer_end;
        }
    }

    void set_verbose_trace(bool verbose_trace) {
        if (grammar_ != nullptr) {
            auto &rule = (*grammar_)[start_];
            rule.verbose_trace = verbose_trace;
        }
    }

    template <typename T = Ast> parser &enable_ast() {
        for (auto &[_, rule] : *grammar_) {
            if (!rule.action) { add_ast_action<T>(rule); }
        }
        return *this;
    }

    template <typename T>
    std::shared_ptr<T> optimize_ast(std::shared_ptr<T> ast,
                                    bool opt_mode = true) const {
        return AstOptimizer(opt_mode, get_no_ast_opt_rules()).optimize(ast);
    }

    void set_logger(Log log) { log_ = log; }

    void set_logger(
        std::function<void(size_t line, size_t col, const std::string &msg)>
            log) {
        log_ = [log](size_t line, size_t col, const std::string &msg,
                     const std::string & /*rule*/) { log(line, col, msg); };
    }

private:
    bool post_process(const char *s, size_t n, Definition::Result &r) const {
        if (log_ && !r.ret) { r.error_info.output_log(log_, s, n); }
        return r.ret && !r.recovered;
    }

    std::vector<std::string> get_no_ast_opt_rules() const {
        std::vector<std::string> rules;
        for (auto &[name, rule] : *grammar_) {
            if (rule.no_ast_opt) { rules.push_back(name); }
        }
        return rules;
    }

    std::shared_ptr<Grammar> grammar_;
    std::string start_;
    bool enablePackratParsing_ = false;
    Log log_;
};

/*-----------------------------------------------------------------------------
 *  enable_tracing
 *---------------------------------------------------------------------------*/

inline void enable_tracing(parser &parser, std::ostream &os) {
    parser.enable_trace(
        [&](auto &ope, auto s, auto, auto &, auto &c, auto &, auto &trace_data) {
            auto prev_pos = std::any_cast<size_t>(trace_data);
            auto pos = static_cast<size_t>(s - c.s);
            auto backtrack = (pos < prev_pos ? "*" : "");
            std::string indent;
            auto level = c.trace_ids.size() - 1;
            while (level--) {
                indent += "│";
            }
            std::string name;
            {
                name = peg::TraceOpeName::get(const_cast<peg::Ope &>(ope));

                auto lit = dynamic_cast<const peg::LiteralString *>(&ope);
                if (lit) { name += " '" + peg::escape_characters(lit->lit_) + "'"; }
            }
            os << "E " << pos + 1 << backtrack << "\t" << indent << "┌" << name
               << " #" << c.trace_ids.back() << std::endl;
            trace_data = static_cast<size_t>(pos);
        },
        [&](auto &ope, auto s, auto, auto &sv, auto &c, auto &, auto len,
            auto &) {
            auto pos = static_cast<size_t>(s - c.s);
            if (len != static_cast<size_t>(-1)) { pos += len; }
            std::string indent;
            auto level = c.trace_ids.size() - 1;
            while (level--) {
                indent += "│";
            }
            auto ret = len != static_cast<size_t>(-1) ? "└o " : "└x ";
            auto name = peg::TraceOpeName::get(const_cast<peg::Ope &>(ope));
            std::stringstream choice;
            if (sv.choice_count() > 0) {
                choice << " " << sv.choice() << "/" << sv.choice_count();
            }
            std::string token;
            if (!sv.tokens.empty()) {
                token += ", token '";
                token += sv.tokens[0];
                token += "'";
            }
            std::string matched;
            if (peg::success(len) &&
                peg::TokenChecker::is_token(const_cast<peg::Ope &>(ope))) {
                matched = ", match '" + peg::escape_characters(s, len) + "'";
            }
            os << "L " << pos + 1 << "\t" << indent << ret << name << " #"
               << c.trace_ids.back() << choice.str() << token << matched
               << std::endl;
        },
        [&](auto &trace_data) { trace_data = static_cast<size_t>(0); },
        [&](auto &) {});
}

/*-----------------------------------------------------------------------------
 *  enable_profiling
 *---------------------------------------------------------------------------*/

inline void enable_profiling(parser &parser, std::ostream &os) {
    struct Stats {
        struct Item {
            std::string name;
            size_t success;
            size_t fail;
        };
        std::vector<Item> items;
        std::map<std::string, size_t> index;
        size_t total = 0;
        std::chrono::steady_clock::time_point start;
    };

    parser.enable_trace(
        [&](auto &ope, auto, auto, auto &, auto &, auto &, std::any &trace_data) {
            if (auto holder = dynamic_cast<const peg::Holder *>(&ope)) {
                auto &stats = *std::any_cast<Stats *>(trace_data);

                auto &name = holder->name();
                if (stats.index.find(name) == stats.index.end()) {
                    stats.index[name] = stats.index.size();
                    stats.items.push_back({name, 0, 0});
                }
                stats.total++;
            }
        },
        [&](auto &ope, auto, auto, auto &, auto &, auto &, auto len,
            std::any &trace_data) {
            if (auto holder = dynamic_cast<const peg::Holder *>(&ope)) {
                auto &stats = *std::any_cast<Stats *>(trace_data);

                auto &name = holder->name();
                auto index = stats.index[name];
                auto &stat = stats.items[index];
                if (len != static_cast<size_t>(-1)) {
                    stat.success++;
                } else {
                    stat.fail++;
                }

                if (index == 0) {
                    auto end = std::chrono::steady_clock::now();
                    auto nano = std::chrono::duration_cast<std::chrono::microseconds>(
                                    end - stats.start)
                                    .count();
                    auto sec = nano / 1000000.0;
                    os << "duration: " << sec << "s (" << nano << "µs)" << std::endl
                       << std::endl;

                    char buff[BUFSIZ];
                    size_t total_success = 0;
                    size_t total_fail = 0;
                    for (auto &[name_, success, fail] : stats.items) {
                        total_success += success;
                        total_fail += fail;
                    }

                    os << "  id       total      %     success        fail  "
                          "definition"
                       << std::endl;

                    auto grand_total = total_success + total_fail;
                    snprintf(buff, BUFSIZ, "%4s  %10zu  %5s  %10zu  %10zu  %s", "",
                             grand_total, "", total_success, total_fail,
                             "Total counters");
                    os << buff << std::endl;

                    snprintf(buff, BUFSIZ, "%4s  %10s  %5s  %10.2f  %10.2f  %s", "", "",
                             "", total_success * 100.0 / grand_total,
                             total_fail * 100.0 / grand_total, "% success/fail");
                    os << buff << std::endl << std::endl;
                    ;

                    size_t id = 0;
                    for (auto &[name_, success, fail] : stats.items) {
                        auto total = success + fail;
                        auto ratio = total * 100.0 / stats.total;
                        snprintf(buff, BUFSIZ, "%4zu  %10zu  %5.2f  %10zu  %10zu  %s", id,
                                 total, ratio, success, fail, name.c_str());
                        os << buff << std::endl;
                        id++;
                    }
                }
            }
        },
        [&](auto &trace_data) {
            auto stats = new Stats{};
            stats->start = std::chrono::steady_clock::now();
            trace_data = stats;
        },
        [&](auto &trace_data) {
            auto stats = std::any_cast<Stats *>(trace_data);
            delete stats;
        });
}
} // namespace peg
